WO2001020733A1 - Light source and wavelength stabilization control method, exposure apparatus and exposure method, method for producing exposure apparatus, and device manufacturing method and device - Google Patents

Light source and wavelength stabilization control method, exposure apparatus and exposure method, method for producing exposure apparatus, and device manufacturing method and device Download PDF

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Publication number
WO2001020733A1
WO2001020733A1 PCT/JP2000/005875 JP0005875W WO0120733A1 WO 2001020733 A1 WO2001020733 A1 WO 2001020733A1 JP 0005875 W JP0005875 W JP 0005875W WO 0120733 A1 WO0120733 A1 WO 0120733A1
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WO
WIPO (PCT)
Prior art keywords
light
wavelength
light source
optical
source device
Prior art date
Application number
PCT/JP2000/005875
Other languages
French (fr)
Japanese (ja)
Inventor
Tomoko Ohtsuki
Soichi Owa
Niichi Atsumi
Masaaki Doi
Original Assignee
Nikon Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP25796999A external-priority patent/JP2001085306A/en
Priority claimed from JP25808999A external-priority patent/JP4362857B2/en
Priority claimed from JP2000190826A external-priority patent/JP2002050815A/en
Application filed by Nikon Corporation filed Critical Nikon Corporation
Priority to EP00956807A priority Critical patent/EP1139521A4/en
Priority to AU68653/00A priority patent/AU6865300A/en
Publication of WO2001020733A1 publication Critical patent/WO2001020733A1/en
Priority to US10/618,590 priority patent/US7098992B2/en

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/0643Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/0648Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/0665Shaping the laser beam, e.g. by masks or multi-focusing by beam condensation on the workpiece, e.g. for focusing
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70Microphotolithographic exposure; Apparatus therefor
    • G03F7/70058Mask illumination systems
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/7055Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
    • G03F7/70566Polarisation control
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/7055Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
    • G03F7/70575Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10007Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
    • H01S3/10015Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by monitoring or controlling, e.g. attenuating, the input signal
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/13Stabilisation of laser output parameters, e.g. frequency or amplitude
    • H01S3/1301Stabilisation of laser output parameters, e.g. frequency or amplitude in optical amplifiers
    • H01S3/13013Stabilisation of laser output parameters, e.g. frequency or amplitude in optical amplifiers by controlling the optical pumping
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35Non-linear optics
    • G02F1/353Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
    • G02F1/354Third or higher harmonic generation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06Construction or shape of active medium
    • H01S3/063Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067Fibre lasers
    • H01S3/06754Fibre amplifiers
    • H01S3/06758Tandem amplifiers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/13Stabilisation of laser output parameters, e.g. frequency or amplitude
    • H01S3/1305Feedback control systems
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/23Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
    • H01S3/2383Parallel arrangements

Definitions

  • the present invention relates to a light source device and a wavelength stabilization control method, an exposure apparatus and an exposure method, a manufacturing method and an exposure apparatus, and a device manufacturing method and a device.
  • the present invention relates to a light source device and a wavelength stabilization control method, an exposure device and an exposure method, a manufacturing method of an exposure device, a device manufacturing method and a device, and more particularly, when manufacturing a semiconductor device, a liquid crystal display device, and the like.
  • the present invention relates to an exposure method using an exposure apparatus, a method for manufacturing the exposure apparatus, a method for manufacturing a device using the exposure apparatus or the exposure method, and a device manufactured by the device manufacturing method.
  • Background art
  • a reduction projection exposure apparatus such as a so-called stepper or a so-called scanning stepper, which performs reduction projection and transfer via an optical system, has become mainstream because of its high throughput.
  • an exposure apparatus such as a projection exposure apparatus requires a high throughput and a high resolution.
  • the resolving power R and depth of focus DOF of the projection exposure apparatus are expressed by the following equations (1) and (2) using the wavelength ⁇ of the exposure illumination light and the numerical aperture of the projection optical system ⁇ . Respectively represented by
  • the simplest and most effective way to reduce the resolution R is to reduce the wavelength ⁇ of the exposure illumination light.
  • g-line and x-ray steppers which use an ultra-high pressure mercury lamp that emits ultraviolet bright lines (g-line, i-line, etc.) as a light source for exposure, have been mainly used as steppers.
  • a KrF excimer laser / stepper using a KrF excimer laser as a light source that outputs a shorter wavelength KrF excimer laser light (wavelength: 248 nm) is becoming mainstream.
  • the development of exposure equipment that uses an ArF excimer laser (wavelength 193 nm) as a shorter wavelength light source is underway.
  • excimer lasers are large, have high energy per pulse, and are liable to damage optical components, and emit toxic fluorine gas.
  • long-wavelength light infrared light and visible light
  • the resulting ultraviolet light is used as exposure light.
  • a light source for exposure employing such a method for example, a light from a laser light generating section provided with a semiconductor laser, as disclosed in Japanese Patent Application Laid-Open No. 8-334483, is used.
  • An array laser which combines a single laser element that generates wavelengths by converting the wavelength with a nonlinear optical crystal provided in the Which is known.
  • the optical output of the entire apparatus can be increased while the optical output of each laser element is kept low.
  • the individual laser elements are independent, it is necessary to make fine adjustments and to adopt a very complicated configuration in order to match the oscillation spectrum of each laser element. Met.
  • a method is conceivable in which one laser oscillation source is used, the laser light emitted from this laser oscillation source is branched, and each branched light is amplified and then wavelength-converted by a common nonlinear optical crystal.
  • this method it is convenient to use an optical fiber to route the laser light, and a configuration is used in which a plurality of light beams emitted from a plurality of bundled optical fibers are incident on the nonlinear optical crystal. Optimum from the viewpoint of simplicity of structure, miniaturization of output beam diameter, and maintainability.
  • the nonlinear optical crystal in order to use the nonlinear optical crystal to efficiently generate second harmonics and the like by the nonlinear optical effect, it is necessary to convert the linearly polarized light in a specific direction according to the crystal direction of the nonlinear optical crystal to the nonlinear optical crystal. It is necessary to make the incident light. However, it is generally difficult to align the directions of linearly polarized light emitted from a plurality of optical fibers. This is the case when a polarization maintaining fiber is used and linearly polarized light is guided. Also, since the optical fiber has a substantially circular cross-sectional shape, the direction of linearly polarized light cannot be specified from the external shape of the optical fiber.
  • the material that can be used for the lens of the projection optical system is currently synthetic quartz, fluorite, Alternatively, it is limited to materials such as fluoride crystals such as lithium fluoride.
  • the excimer laser beam is used. Therefore, it is necessary to narrow the oscillation spectrum width, that is, to narrow the bandwidth of the wavelength.
  • the narrowing of the wavelength can be achieved, for example, by using a narrowing module (for example, a combination of a prism and a grating (diffraction grating) or an optical element such as an etalon) provided in a laser resonator.
  • the so-called wavelength is used to keep the spectral width of the wavelength of the excimer laser light supplied to the projection optical system during exposure to a predetermined wavelength width, and to maintain the center wavelength at the predetermined wavelength at the same time. Stabilization control is required.
  • the wavelength monitor section of an excimer laser device is generally configured around a Fabry-Perot etalon (hereinafter, also referred to as an “etalon element”), which is a Fabry-Perot spectrometer.
  • etalon element Fabry-Perot etalon
  • the pattern line width is becoming increasingly finer as semiconductor devices become more highly integrated. It has become.
  • the overlay accuracy depends on how to suppress aberrations such as distortion components of the projection optical system.
  • the exposure apparatus has been required to have stability in the center wavelength of the illumination light for exposure and an increasingly narrower band.
  • a single-wavelength light source as the light source itself.
  • the projection optical system is adjusted only to the predetermined exposure wavelength, if the center wavelength cannot be stably maintained, chromatic aberration of the projection optical system will result, Maintaining the stability of the center wavelength is indispensable because the imaging characteristics such as distortion and focus fluctuate.
  • an exposure apparatus is required to realize an exposure amount control performance adapted to a difference in a resist sensitivity or the like for each wafer, and a wide dynamic range, typically about 1 to 1/7 is required.
  • an energy rough adjuster such as an ND filter is used for controlling the exposure amount according to the above-described difference in resist sensitivity or the like for each wafer.
  • the current exposure apparatus has a light amount control performance (hereinafter, appropriately referred to as a “first exposure amount control performance”) according to the above-described differences in the resist sensitivity for each wafer, as well as a shot area within the same wafer. (Exposure amount system) to correct process variation for each (chip) Control performance (hereinafter referred to as “second exposure control performance” as appropriate). Further, in the case of the scanning step, an exposure amount control performance (hereinafter, appropriately referred to as “third exposure amount control performance”) for realizing line width uniformity in the shot area is further required.
  • the dynamic range is controlled to the set value within about ⁇ 10% of the set exposure amount and the shot-to-shot stepping time of about 100 ms as the second exposure amount control performance described above.
  • the required control accuracy is about 1% of the set exposure.
  • the control accuracy is typically set to ⁇ 0.2% of the set exposure amount within a time period of 20 msec, which is an exposure time of 1 shot. A control speed of about 1 ms is required.
  • a light source device capable of performing control according to a request required for control is expected as a light source of an exposure device.
  • the requirements required for control include (a) dynamic range of control, (b) control accuracy, (c) control speed, (d) degree of linearity between detected light intensity and control amount, and (e) This is an energy save function for power saving.
  • the present invention has been made under such circumstances, and a first object of the present invention is to provide a light source device that can perform light amount control according to a request necessary for the above control.
  • a second object of the present invention is to provide a light source device that can reliably maintain the center wavelength of laser light at a predetermined set wavelength.
  • a third object of the present invention is to provide a light source device capable of generating predetermined light while controlling the polarization state with a simple configuration.
  • a fourth object of the present invention is to provide a wavelength stabilization control method that can reliably maintain the center wavelength of laser light at a predetermined set wavelength.
  • the fifth object of the present invention is to easily realize required exposure amount control.
  • An exposure apparatus is provided.
  • a sixth object of the present invention is to provide an exposure apparatus that can perform high-precision exposure without being affected by a change in the temperature of the atmosphere.
  • a seventh object of the present invention is to provide an exposure apparatus capable of performing exposure with high accuracy regardless of a change in sensitivity characteristics of a photosensitive agent.
  • An eighth object of the present invention is to provide an exposure apparatus capable of efficiently transferring a predetermined pattern onto a substrate.
  • a ninth object of the present invention is to provide an exposure method capable of easily achieving required exposure amount control.
  • a tenth object of the present invention is to provide an exposure method capable of performing high-precision exposure without being affected by temperature fluctuations of the atmosphere.
  • a first object of the present invention is to provide a device manufacturing method capable of improving the productivity of a highly integrated microdevice. Disclosure of the invention
  • a light source device for generating light of a single wavelength, comprising: a light generating unit for generating light of a single wavelength; and a light source unit arranged in parallel at an output stage of the light generating unit.
  • a fiber group consisting of a plurality of optical fibers; and a light amount control device for controlling the light amount of light output from the fiber group by individually turning on and off the light output from each of the optical fibers. 1 is a light source device.
  • light of a single wavelength generated by the light generation unit travels toward each of a plurality of optical fibers constituting a group of fibers arranged in parallel at its output stage.
  • the amount of light output from the group of optical fibers is controlled.
  • a plurality of levels of light quantity control in proportion to the number of optical fibers can be performed, so that a wide dynamic range can be easily realized.
  • the performances (including the fiber diameter etc.) of each optical fiber may be different, but if the performances of each optical fiber are almost the same, the same amount of light from each of the optical fibers
  • N-level light quantity control according to the number N of optical fibers can be executed accurately and reliably. Therefore, for example, if N ⁇ 100, the light amount can be controlled with an accuracy of 1% or less. In this case, the degree of linearity between the control amount and the light amount is good.
  • an energy coarse adjuster such as an ND filter is not required, various problems such as deterioration of the light quantity control performance due to durability of the filter, a change with time in transmittance, and the like can be improved.
  • the plurality of optical fibers constituting the fiber group may be bundled at least at their output ends to form a bundle-fiber.
  • the diameter of an optical fiber is small, so that even if 100 or more fibers are bundled, the diameter can be kept within several mm, and some optical element, for example, a quarter
  • an optical element such as a nonlinear optical crystal constituting a wave plate or a wavelength converter, a small optical element can be arranged.
  • the method of turning on / off the light output from each optical fiber includes, for example, a mechanical or electrical shirt that blocks incident light to each optical fiber, or There are various possibilities, such as providing a mechanical or electrical shutter that blocks the emission of light.
  • a fiber that can perform optical amplification is provided in a part of each optical path that includes the optical fiber.
  • the light quantity control device controls the on / off of the optical output from each of the optical fibers by changing the intensity of the excitation light from the excitation light source of the fiber amplifier. The switching may be performed.
  • At least one stage of fiber amplifier capable of performing optical amplification is provided in a part of each optical path including each optical fiber” means that each optical path When the optical path has an optical amplifier provided at the input stage separately from the optical fiber, this includes any case where a part of the optical fiber constituting each optical path is a fiber amplifier.
  • the light incident on the optical path including each optical fiber can be amplified by the fiber amplifier, and the pumping light for the optical amplifier provided in the optical path including the optical fiber whose optical output is turned off is turned off. Since the intensity level is set low (including zero), energy saving is possible. Further, since the light output is turned on and off by switching the intensity of the pump light from the pump light source of the fiber amplifier, the light output can be turned on and off in a shorter time than when a shutter or the like is used. In the first light source device of the present invention, when the on / off of the optical output from each optical fiber is performed by switching the intensity of the excitation light from the excitation light source of the fiber amplifier, the intensity level of the excitation light is switched.
  • the light amount control device may selectively set the intensity of the excitation light from the excitation light source to a predetermined level or a zero level.
  • the intensity of the excitation light may be switched by setting to.
  • the light quantity control device may set the intensity of the excitation light to one of a predetermined level and a zero level by turning on and off the excitation light source.
  • the light amount control device when the on / off of the optical output from each optical fiber is performed by switching the intensity of the excitation light from the excitation light source of the fiber amplifier, the light amount control device includes: By setting the intensity of the excitation light from the excitation light source to one of a predetermined first level and a second level smaller than the first level, the intensity of the excitation light is switched. Is also good. That is, in a fiber amplifier, if the intensity of the pump light is not more than zero, if the intensity is not more than a predetermined value, light absorption occurs, and the intensity of the light emitted from the fiber amplifier becomes almost zero.
  • the optical output from the optical fiber can be turned on / off.
  • the first level and the second level may be two non-fixed levels within a predetermined range.
  • the light amount control device turns on / off the light output from each of the optical fibers in a final stage. This may be performed by switching the intensity of the excitation light from the excitation light source of the fiber amplifier. In such a case, avoid the adverse effect of ASE (Amplified Spontaneous Emission), which is a problem when switching the intensity of the pump light from the pump light source of the fiber amplifier other than the last stage.
  • ASE Amplitude Modifying
  • the later fiber requires higher pumping light intensity, so that the power saving effect of the pumping light source when the light output from the optical fiber is turned off is further increased.
  • the fiber amplifier of the last stage has a larger mode field diameter than the fiber amplifiers of the other stages. In such a case, an increase in the spectrum width of the amplified light due to the non-linear effect in the optical fiber can be avoided.
  • the first light source device of the present invention further includes a storage device in which an output intensity map corresponding to the on / off status of the optical output from each of the optical fibers is stored in advance, and the light intensity control device includes:
  • the light output from each of the optical fibers may be individually turned on / off based on a map and a predetermined set light amount. In such a case, even if there is a variation in the output of each optical fiber, the optical output of the fiber group can be made substantially equal to the set light amount, and optical fibers having various performances can be used.
  • the output intensity map is created based on the dispersion of each fiber output measured in advance.
  • the output intensity map is created based on the dispersion of each fiber output actually measured in advance, the light output of the fiber group can be surely matched with the set light amount.
  • the output intensity map is obtained by measuring the fiber output measured in advance. It is desirable that the power supply should be created in further consideration of the output variation caused by the wavelength conversion efficiency variation corresponding to the above. In such a case, even if the wavelength conversion efficiency with respect to the optical output from each optical fiber varies, the amount of output light can be controlled to the set amount.
  • the light generation unit generates a single-wavelength laser light within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser light. It is good.
  • the light generation unit generates a single-wavelength laser light having a wavelength of about 0.5 m, and the wavelength conversion unit generates an eighth harmonic and a 1st harmonic of the laser light having a wavelength of about 1.5 / m. Either of the 0th harmonic can be generated.
  • the first light source device of the present invention may further include a wavelength converter for converting a wavelength of the light output from each of the optical fibers.
  • the output of the wavelength converter is proportional to the number of fibers whose optical output is on. For this reason, for example, when the performances of the respective optical fibers are substantially the same, the same amount of light can be output from each of the optical fibers. As a result, the amount of light can be controlled with good linearity.
  • the light generation unit generates a single-wavelength laser light within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser light. It is good.
  • the light generating section generates a single-wavelength laser light having a wavelength of about 1.5 tm
  • the wavelength converting section generates an eighth harmonic of the laser light having a wavelength of about 1.5 m and 10 times higher. Any of the harmonics can be generated.
  • the light generating unit generates light having a single wavelength.
  • a light source, and a light modulator that converts the light from the light source into a pulsed light having a predetermined frequency and outputs the pulsed light.
  • At least one of the peak powers may be further controlled.
  • fine adjustment of the light amount between each step is performed by the pulse light output from the optical modulator. Control is possible by controlling at least one of the frequency and the peak power, and consequently the light amount can be continuously controlled. If the set exposure amount is set to any value within the predetermined range, the output light amount can be reduced. It is possible to match the set light quantity.
  • the first light source device of the present invention may further include a delay unit that individually delays the optical output from each of the plurality of optical fibers and shifts the optical output in time. In such a case, the lights output from the optical fibers do not overlap with each other in time, so that spatial coherency can be reduced as a result.
  • the light generation unit when the light generation unit has a laser light source that oscillates laser light, the light generation unit relates to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength.
  • a beam monitor mechanism for monitoring the optical characteristics of the laser light, and a wavelength calibration control device for performing wavelength calibration based on the temperature dependence data of the detection reference wavelength of the beam monitor mechanism. Can be provided.
  • the wavelength calibration controller performs the wavelength calibration based on the data on the temperature dependence of the detection reference wavelength of the beam monitor mechanism, so that the detection reference wavelength of the beam monitor mechanism is set to the set wavelength.
  • a polarization adjusting device for aligning the polarization states of a plurality of light beams having the same wavelength through the plurality of optical fibers; and a plurality of linearly polarized lights having the same polarization direction for all the light beams through the plurality of optical fibers.
  • a polarization direction conversion device for converting the light into a light flux.
  • the fiber amplifier when at least one stage of fiber amplifier capable of performing optical amplification is provided in a part of each optical path including the optical fiber, the fiber amplifier is a rare earth element.
  • An optical fiber mainly composed of either a phosphate glass to which an element is added or a bismuth oxide-based glass can be provided as an optical waveguide member.
  • a light source device for generating light of a single wavelength, a light source for generating light of a single wavelength, and converting light from the light source into pulse light of a predetermined frequency.
  • An optical modulator having an optical modulator for outputting the optical signal; an optical amplifier including at least one fiber amplifier for amplifying the pulse light generated by the optical generator; and an optical amplifier output from the optical modulator.
  • a light amount control device that controls the light amount of the output light from the fiber amplifier by controlling the frequency of the pulse light.
  • the light generator in the light generator, light of a single wavelength is generated from the light source, and the light is converted into pulse light of a predetermined frequency by the optical modulator and output.
  • the pulse light is amplified by the optical amplifier and output as a pulse light having a higher peak power.
  • the peak power of the pulsed light is almost constant, the light amount per unit time (integrated light amount) increases or decreases according to the frequency.
  • the light intensity of the output light from the fiber amplifier can be made to match the set light intensity (target light intensity).
  • the light intensity control device includes: The frequency of the pulse light output from the optical modulator may be controlled based on a predetermined light amount.
  • the frequency of the pulse light output from the optical modulator may be controlled based on a predetermined light amount.
  • the intensity of the input light of the optical amplifier changes according to the frequency of the pulse light from the optical modulator, the gain of the fiber amplifier constituting the optical amplifier has input light intensity dependence.
  • high-precision light quantity control can be performed without being affected by a change in the peak power of the output pulse from the optical amplifier due to the input light intensity dependency.
  • the light amount control device may further control the peak power of the pulse light output from the optical modulator. In such a case, even if the peak power of the pulsed light fluctuates, accurate light amount control can be performed.
  • the light amount control device controls the frequency of a voltage pulse applied to the optical modulator, thereby controlling the pulse.
  • the frequency of light may be controlled.
  • the frequency of the output pulse light of the electro-optical modulator matches the frequency of the voltage pulse applied to the optical modulator.
  • a plurality of the optical amplifiers may be provided in parallel, and an optical output end of each of the optical amplifiers may be configured by an optical fiber.
  • the plurality of optical fibers constituting the plurality of optical amplifiers may be bundled to form a bundle-fiber.
  • the diameter of an optical fiber is small, so that even if 100 or more fibers are bundled, the diameter can be kept within about several mm, and some kind of optical element is arranged in the output stage of one fiber of the bundle. In this case, a small optical element can be arranged.
  • the second light source device of the present invention may further include a wavelength converter for converting a wavelength of light output from the optical amplifier.
  • the light amount of the output light from the wavelength conversion unit becomes a value corresponding to the output intensity (light amount) of the pulse light from the optical amplifying unit and eventually from the optical modulator.
  • the value is not necessarily proportional to the input intensity (light intensity) of the pulsed light.
  • the peak intensity of the output pulse of the optical amplifier is at most a power of the order of the harmonic output from the wavelength converter. It shows a proportional non-linear dependence.
  • the optical modulator is an electro-optical modulator
  • the dependence of the pulse peak intensity of the output light on the pulse peak intensity of the voltage pulse applied to the electro-optical modulator is cos (V). Therefore, the above-described nonlinear dependence of the wavelength conversion unit is reduced. Therefore, when a wavelength converter is provided, it is preferable that the optical modulator is an electro-optical modulator.
  • the light generation unit generates a single-wavelength laser light within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser light. It is good.
  • the light generating section generates a single-wavelength laser light having a wavelength of about 1.5 tm
  • the wavelength converting section generates an eighth harmonic of the laser light having a wavelength of about 1.5 m and 10 times higher. Any of the harmonics can be generated.
  • a light source device for generating light of a single wavelength, a light source for generating light of a single wavelength, and converting light from the light source into pulse light of a predetermined frequency.
  • An optical modulator having an optical modulator for outputting the optical signal; an optical amplifier including at least one fiber amplifier for amplifying the pulse light generated by the optical generator; and an optical amplifier output from the optical modulator.
  • a light amount control device that controls the light amount of the output light from the optical amplifier by controlling the peak power of the pulse light.
  • the light generation section light of a single wavelength is generated from the light source, and the light is emitted. Is converted into pulsed light of a predetermined frequency by the optical modulator and output.
  • the pulse light is amplified by the optical amplifier and output as a pulse light having a higher peak power.
  • the amount of light (integrated light) per unit time of the pulse light output from the optical amplifier naturally increases or decreases according to the peak power of the pulse light from the optical modulator. Therefore, the light amount control device is output from the optical modulator.
  • the light quantity of the output light from the fiber amplifier can be made to match the set light quantity (target light quantity).
  • the light amount can be adjusted more quickly and more finely than in the first light source device described above, and the set light amount is within a predetermined range. If there is any value, the light quantity can be made to substantially match.
  • the light intensity control device includes the output intensity map.
  • the peak power of the pulse light output from the optical modulator may be controlled based on the predetermined light amount. In such a case, high-precision light quantity control is performed without being affected by the change in the peak power of the output pulse from the optical amplifier due to the input light intensity dependence of the gain of the fiber amplifier constituting the optical amplifier. It becomes possible.
  • the optical modulator is an electro-optic modulator
  • the light amount control device controls the peak level of a voltage pulse applied to the optical modulator, thereby controlling the pulse level.
  • the peak power of light may be controlled.
  • the pulse peak intensity of the output light from the electro-optic modulator depends on the pulse peak intensity of the voltage pulse applied to the electro-optic modulator.
  • a plurality of the optical amplifiers may be provided in parallel, and an optical output end of each of the optical amplifiers may be constituted by an optical fiber.
  • the plurality of optical fibers constituting each of the plurality of optical amplifiers may be bundled to form a bundle of fibers.
  • the optical fiber Since the diameter of the fiber is small, it can be kept within a few millimeters even if 100 or more fibers are bundled. Elements can be arranged.
  • the plurality of optical amplifiers are provided in parallel, and the optical output terminals of the respective optical amplifiers are each configured by an optical fiber.
  • a delay unit may be further provided for individually delaying the optical output from each of the above, and performing the optical output in a time-shifted manner. In such a case, the lights output from the respective optical fibers do not overlap in time, and as a result, the spatial coherency can be reduced.
  • the third light source device of the present invention may further include a wavelength conversion unit that converts a wavelength of light output from the optical amplification unit.
  • the light quantity of the output light from the wavelength conversion unit is determined by the output of the optical amplification unit, and thus the input intensity of the pulse light from the optical modulator
  • the value is not necessarily proportional to the input intensity (light intensity) of the pulsed light.
  • the peak intensity of the output pulse of the optical amplifier is at most a power of the order of the harmonic output from the wavelength converter. It shows a proportional non-linear dependence.
  • the optical modulator is an electro-optical modulator, the dependence of the pulse peak intensity of the output light on the pulse peak intensity of the voltage pulse applied to the electro-optical modulator is cos (V). Therefore, the above-described nonlinear dependence of the wavelength conversion unit is reduced. Therefore, when a wavelength converter is provided, it is preferable that the optical modulator is an electro-optical modulator.
  • the light generation unit generates a laser beam of a single wavelength within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser beam. It is good.
  • the light generation unit generates a single-wavelength laser light having a wavelength of around 1.5 / _t m, and the wavelength conversion unit generates an 8th harmonic of the laser light having a wavelength of around 1.5 m and Either of the tenth harmonic can be generated.
  • the light generation unit has a laser light source that oscillates laser light as the light source, the center wavelength of the laser light is maintained at a predetermined set wavelength.
  • Beam monitoring mechanism for monitoring the optical characteristics of the laser light related to wavelength stabilization for performing wavelength calibration; and wavelength calibration for performing wavelength calibration based on data on the temperature dependence of the detection reference wavelength of the beam monitoring mechanism.
  • a control device since the wavelength calibration is performed by the wavelength calibration control device based on the temperature dependence data of the detection reference wavelength of the beam monitor mechanism, the detection reference wavelength of the beam monitor mechanism is set to the set wavelength. It is possible to accurately set the center wavelength of the laser beam to a predetermined set wavelength using the beam monitor mechanism without being affected even if the temperature or the like of the atmosphere of the beam monitor mechanism fluctuates. Wavelength stabilization control that can be maintained becomes possible.
  • the apparatus may further include an adjustment device; and a polarization direction conversion device that converts all light beams passing through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
  • the fiber amplifier may include, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
  • a laser light source that oscillates laser light; and monitors an optical characteristic of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength.
  • a fourth light source device comprising: a beam monitor mechanism for performing a wavelength calibration based on data on the temperature dependence of a detection reference wavelength of the beam monitor mechanism.
  • the first control device sets the detection reference wavelength of the beam monitor mechanism. Wavelength calibration is performed based on the temperature dependence data. For this reason, the detection reference wavelength of the beam monitor mechanism can be accurately set to the set wavelength, so that even if the temperature or the like of the atmosphere of the beam monitor mechanism fluctuates, the beam monitor mechanism is not affected.
  • the wavelength stabilization control that ensures that the center wavelength of the laser light is maintained at a predetermined set wavelength can be performed by using.
  • the first control device may determine the absolute wavelength provided from the absolute wavelength providing source. Absolute wavelength calibration is performed so that the detection reference wavelength of the beam monitor mechanism substantially matches, and a setting wavelength calibration that matches the detection reference wavelength with the setting wavelength is performed based on the temperature dependency data. Can be. In such a case, the first control device performs absolute wavelength calibration for making the detection reference wavelength of the beam monitor mechanism substantially coincide with the absolute wavelength provided from the absolute wavelength providing source. Based on the temperature dependency data, a set wavelength calibration for matching the detection reference wavelength to the set wavelength is performed.
  • the set wavelength calibration is performed to match the detection reference wavelength of the beam monitor mechanism after the absolute wavelength calibration to the set wavelength. .
  • the detection reference wavelength of the beam monitor mechanism can always be accurately set to the set wavelength, and therefore, even if the temperature of the atmosphere of the beam monitor mechanism fluctuates, it is affected by the fluctuation. Instead, it is possible to perform wavelength stabilization control by using a beam monitor mechanism to reliably maintain the center wavelength of the laser beam at a predetermined set wavelength.
  • absolute wavelength close to the set wavelength is a concept that includes the same wavelength as the set wavelength.
  • the beam monitoring mechanism includes a Fabry-Perot etalon
  • the temperature-dependent data includes a resonance wavelength of the Fabry-Perot etalon.
  • the wavelength calibration and the set wavelength calibration may be performed. In such a case, it is possible to set the detection reference wavelength to the set wavelength by using the temperature dependence of the resonance wavelength, which is the reference for the wavelength detection of Fabry-Perot etalon.
  • the temperature dependency data further includes temperature dependency data of a center wavelength of the laser light oscillated from the laser light source
  • the first control device includes:
  • the wavelength control of the laser light source may be performed together.
  • the above-described absolute wavelength calibration can be completed in a shorter time than when the wavelength control of the laser beam is not performed.
  • the fourth light source device of the present invention may further include a fiber amplifier for amplifying the laser light from the laser light source.
  • the laser light from the laser light source can be amplified by the fiber amplifier. Therefore, even when the required light amount is large, a small laser light source such as a DFB semiconductor laser or a fiber laser can be used. It is possible to use a solid-state laser such as that described above, and it is possible to reduce the size and weight of the device.
  • a wavelength converter including a non-linear optical crystal for converting the wavelength of the amplified laser light May be further provided.
  • the wavelength conversion of the laser light amplified by the wavelength converter becomes possible.
  • the absolute wavelength providing source receives the laser light.
  • the first control device when performing the absolute wavelength calibration, maximizes absorption of an absorption line closest to the set wavelength of the absorption cell, and the Fabry-Perot etalon The maximum transmittance may be set to be maximum.
  • the absorption line closest to the set wavelength includes “the absorption line having the same wavelength as the set wavelength”.
  • the wavelength of the laser light from the laser light source is determined based on a monitoring result of the beam monitoring mechanism after the completion of the setting wavelength calibration.
  • a second control device that performs feedback control of the control.
  • the wavelength of the laser beam from the laser light source is controlled by the second control device based on the monitoring result of the beam monitor mechanism in which the detection reference wavelength is accurately set to the set wavelength.
  • the wavelength of the laser beam can be stably maintained at the set wavelength.
  • a fourth light source device a plurality of optical amplifiers each including a fiber amplifier and arranged in parallel at an output stage of the laser light source; and the plurality of optical amplifiers respectively configuring the plurality of optical amplifiers.
  • a polarization adjusting device for aligning the polarization states of a plurality of light beams of the same wavelength through a fiber; and a polarization direction conversion device for converting all the light beams through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
  • the fiber amplifier may include, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
  • a fifth aspect of the present invention there are provided: a plurality of optical fibers; a polarization adjusting device for aligning a polarization state of a plurality of light beams having the same wavelength via the plurality of optical fibers; All the luminous fluxes into a plurality of linearly polarized light beams having the same polarization direction.
  • a fifth light source device comprising: a polarization direction conversion device that converts the light into a light beam.
  • the polarization direction conversion device converts all the light beams passing through the plurality of optical fibers into the same polarization direction. Since the light beam is converted into a plurality of linearly polarized light beams, a plurality of linearly polarized light beams having the same polarization direction can be obtained with a simple configuration.
  • the polarization direction conversion device is configured to be a quarter.
  • a configuration having a single wavelength plate can be employed.
  • the plurality of light beams passing through each optical fiber are substantially circularly polarized by the polarization adjusting device, all of the plurality of light beams are transmitted through the quarter-wave plate of the polarization direction conversion device. By doing so, it can be converted into a plurality of linearly polarized light beams having the same polarization direction. Therefore, it is possible to convert a plurality of light beams into a plurality of linearly polarized light beams having the same polarization direction while having a very simple configuration of the polarization direction conversion device as one quarter-wavelength plate. it can.
  • the polarization direction of the linearly polarized light is determined by the direction of the optical axis of the crystal material or the like forming the quarter-wave plate. Therefore, by adjusting the direction of the optical axis of the crystal material or the like forming the quarter-wave plate, it is possible to obtain a plurality of luminous fluxes having any given linear polarization direction.
  • the polarization adjusting device may be configured to set the polarization state of each of the plurality of light beams incident on each of the optical fibers to substantially circular polarization. it can. This is because when circularly polarized light is incident on an optical fiber having a cylindrically symmetric structure, circularly polarized light is emitted from the optical fiber. Since it is impossible to make the optical fiber completely cylindrically symmetric, it is preferable that the length of the optical fiber is short.
  • the polarization direction conversion may be performed.
  • a configuration having a half-wave plate and a quarter-wave plate optically connected in series can be employed.
  • the half-wave plate and the quarter-wave plate are connected in series, either of them may be arranged on the upstream side in the optical path.
  • the polarization plane of a plurality of light beams passing through each optical fiber is similarly rotated by passing through a common half-wave plate.
  • a common quarter-wave plate By passing through a common quarter-wave plate, all the light beams become linearly polarized light having the same polarization direction.
  • the quarter-wave plate is arranged on the upstream side, as in the case where the half-wave plate is arranged on the upstream side, all light beams should be linearly polarized light having the same polarization direction. Can be.
  • the polarization direction changing device can have a simple configuration of one half-wave plate and one quarter-wave plate.c
  • the half-wave plate and the quarter-wave plate By adjusting the direction of the optical axis of a crystal material or the like forming a single-wavelength plate, it is possible to obtain a plurality of luminous fluxes having arbitrary identical linear polarization directions.
  • each of the plurality of optical fibers constitutes an optical fiber amplifier in which each of the plurality of light beams incident on the plurality of optical fibers is light to be amplified.
  • the configuration may be an optical fiber through which the target light is guided.
  • each of them since the light incident on each optical fiber is amplified from each optical fiber and emitted from each optical fiber, each of them has high intensity and the same polarization as the light emitted from the polarization direction conversion device.
  • a plurality of linearly polarized light beams having directions can be obtained. As a result, it is possible to increase the amount of emitted light as a light source device.
  • the optical fiber may be formed mainly of one of a phosphite glass to which a rare earth element is added and a bismuth oxide-based glass.
  • each of the plurality of light beams incident on the plurality of optical fibers may be a pulse light train.
  • the repetition period and pulse height of the light pulse in each pulse light train By adjusting the repetition period and pulse height of the light pulse in each pulse light train, the amount of emitted light as a light source device can be controlled with high accuracy.
  • each of the plurality of light beams incident on the plurality of optical fibers is a light beam amplified by one or more stages of optical fiber amplifiers before being incident on the plurality of optical fibers. It can be. In such a case, the amount of emitted light as a light source device can be increased by one-stage or multi-stage optical amplification by one or more stages of optical fiber amplifiers.
  • the polarization adjusting device adjusts a mechanical stress or the like applied to each of the plurality of optical fibers disposed immediately before the polarization direction changing device, and adjusts the polarization direction changing device. It is also possible to adjust the polarization state of the plurality of incident light beams.However, the polarization adjusting device controls the optical characteristics of optical components disposed upstream of the plurality of optical fibers to adjust the polarization. The configuration can be performed. In such a case, the plurality of optical fibers disposed immediately before the polarization direction conversion device are optical fibers having an optical amplifier and guiding the light to be amplified, and the polarization is adjusted by applying stress or the like.
  • the polarization adjustment located on the more upstream side controls the optical characteristics of the optical components that are slower, so that the polarization state of multiple light beams incident on the polarization direction conversion device is aligned. be able to.
  • the plurality of optical fibers may be bundled substantially in parallel with each other.
  • the section occupied by the plurality of optical fibers can be reduced, and the light receiving area of the polarization direction conversion device can be reduced, so that the light source device can be downsized.
  • the fifth light source device may further include a wavelength converter that performs wavelength conversion by passing the light beam emitted from the polarization direction conversion device through at least one nonlinear optical crystal.
  • the polarization direction of the light beam emitted from the polarization direction conversion device should be set to the polarization direction of the incident light at which the wavelength conversion (double harmonic generation, sum frequency generation) is performed efficiently by the nonlinear optical crystal. To Thus, the wavelength-converted light can be generated and emitted more efficiently.
  • the light emitted from the plurality of optical fibers has one of infrared and visible wavelengths, and the light emitted from the wavelength converter has an ultraviolet wavelength.
  • the light emitted from the wavelength converter has an ultraviolet wavelength.
  • ultraviolet light suitable for transferring a fine pattern can be efficiently generated.
  • the light emitted from the plurality of optical fibers has a wavelength of about 147 nm, and the light emitted from the wavelength converter has a wavelength of about 193.4 nm. It can be. In such a case, it is possible to efficiently obtain light having a wavelength obtained when the ArF excimer laser light source is used.
  • an optical amplifier that includes an optical waveguide member mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass, and amplifies incident light; A wavelength converter that converts a wavelength of light emitted from the amplifier.
  • a conventional optical waveguide member such as an amplification fiber or the like, which is mainly made of silica glass and to which a rare earth element is added
  • it is mainly made of phosphate glass or bismuth oxide-based glass. Since an optical waveguide member to which a rare earth element is added is used, incident light can be amplified with a high amplification factor by an optical waveguide member having a short length. For this reason, it is possible to supply high-luminance light to the wavelength converter while reducing the change in the polarization state caused by passing through the optical waveguide member.
  • the optical waveguide member may be configured as an optical fiber having a core for guiding light and a clad provided around the core.
  • This fiber also has a double clad double clad structure. It may be a double fiber structure. In such a case, connection to a propagation fiber used for guiding light becomes easy, and a light source device can be realized more easily.
  • the optical fiber can be laid in a straight line. In such a case, it is possible to prevent the occurrence of radial stress asymmetry which causes a change in the polarization state, so that it is possible to obtain output light that maintains the polarization state at the time of incidence.
  • the optical amplifier may further include a container accommodating at least the optical fiber.
  • a container accommodating at least the optical fiber.
  • the wavelength converter may be configured to include at least one nonlinear optical crystal that performs wavelength conversion of incident light.
  • high-output wavelength-converted light can be obtained by irradiating the nonlinear optical crystal with high-luminance light emitted from the optical amplifier.
  • a wavelength stabilization control method for maintaining a center wavelength of a laser beam oscillated from a laser light source at a predetermined set wavelength, wherein the wavelength of the laser beam is detected.
  • the “absolute wavelength close to the set wavelength” is a concept including the same wavelength as the set wavelength.
  • the temperature dependence of the detection reference wavelength of the wavelength detection device that detects the wavelength of the laser light in the first step is measured in advance.
  • wavelength detection is performed for the absolute wavelength provided by the absolute wavelength source that provides the absolute wavelength close to the set wavelength.
  • Absolute wavelength calibration is performed so that the detection reference wavelength of the device is almost the same.
  • the detection reference wavelength of the wavelength detector is set to the set wavelength.
  • the detection reference wavelength of the wavelength detection device after the absolute wavelength calibration is set to the set wavelength using the temperature dependency of the detection reference wavelength of the wavelength detection device measured in advance.
  • the detection reference wavelength of the wavelength detecting device can always be accurately set to the set wavelength, so that even if the temperature of the atmosphere of the wavelength detecting device fluctuates, the wavelength can be detected without being affected by the fluctuation.
  • wavelength stabilization control that ensures that the center wavelength of the laser beam is maintained at a predetermined set wavelength becomes possible.
  • the wavelength detection device is a Fabry-Perot etalon
  • the temperature dependence of the resonance wavelength of the wavelength detection device is measured in the first step
  • the temperature of the wavelength detection device is measured in the second step.
  • the resonance wavelength may be set to substantially coincide with the absolute wavelength by controlling the temperature
  • the temperature of the wavelength detection device may be controlled in the third step to set the resonance wavelength to the set wavelength.
  • the absolute wavelength providing source is an absorption cell on which the laser light is incident
  • absorption of an absorption line closest to the set wavelength of the absorption cell becomes maximum.
  • the transmittance of the wavelength detection device may be maximized.
  • the absorption line closest to the set wavelength includes “the absorption line having the same wavelength as the set wavelength”.
  • the temperature dependence of the center wavelength of the laser light is also measured in advance, and in the second step, the wavelength control of the laser light is also performed. It is good. In such a case, the absolute wavelength key Replenishment can be completed in a shorter time than when laser wavelength control is not performed.
  • the wavelength of the laser light from the laser light source is controlled based on a detection result of the wavelength detection device in which the detection reference wavelength is set to the set wavelength in the third step.
  • a fourth step may be further included.
  • the wavelength of the laser light from the laser light source is controlled based on the detection result of the wavelength detection device whose detection reference wavelength is accurately set to the set wavelength, the wavelength of the laser light is controlled. It can be stably maintained at the set wavelength.
  • the wavelength control of the laser light may be performed by controlling at least one of a temperature of the laser light source and a supply current.
  • a temperature of the laser light source For example, in the case of a single-wavelength oscillation laser such as a DFB semiconductor laser or a fiber laser, the oscillation wavelength of the laser can be controlled by controlling the temperature.
  • the supply current drive current
  • the oscillation wavelength of the laser can be controlled.
  • an exposure apparatus for transferring a pattern formed on a mask onto a substrate, wherein the exposure apparatus generates a single-wavelength laser beam within a range from an infrared region to a visible region.
  • a generating unit a fiber group composed of a plurality of optical fibers arranged in parallel at an output stage of the light generating unit; and an optical output from each of the optical fibers by individually turning on and off the optical output from each of the optical fibers.
  • a light amount control device that controls the amount of laser light to be output; a wavelength conversion unit that converts the wavelength of the laser light output from each of the optical fibers and outputs ultraviolet light that is a harmonic of the laser light; An illumination optical system for illuminating the mask using the ultraviolet light output from the wavelength conversion unit as illumination light for exposure;
  • the mask is illuminated with the ultraviolet light output from the wavelength conversion unit by the illumination optical system as illumination light for exposure, and the pattern formed on the mask is transferred onto the substrate.
  • the amount of ultraviolet light applied to the mask by the light amount control device Since the control can be performed in response to a necessary request, the required exposure control can be realized as a result.
  • the apparatus further comprises a storage device in which an output intensity map corresponding to the ON / OFF state of the optical output from each of the optical fibers is stored in advance, and the light amount control device is configured to store the output intensity map and a predetermined setting.
  • the light output from each of the optical fibers may be individually turned on / off based on the light amount to control the light amount of the laser light output from the fiber group. In such a case, even if there is a variation in the output of each optical fiber, the optical output of the fiber group can be made substantially equal to the set light amount, and optical fibers having various performances can be used.
  • the light generation unit includes: a light source that generates laser light of a single wavelength; and an optical modulator that converts light from the light source into pulse light of a predetermined frequency and outputs the pulse light.
  • the light quantity control device further controls the light quantity of the laser light output from the fiber group by controlling the frequency of the pulse light output from the optical modulator. can do.
  • the light amount control device allows the light modulator to finely adjust the light amount between each stage. It becomes possible by controlling the frequency of the output pulse light. As a result, continuous control of the light amount is possible, and the light amount of the output light can be made to match the set light amount regardless of the set light amount within a predetermined range. Therefore, more accurate exposure amount control becomes possible.
  • the light amount control device further controls a light amount of the laser light output from the fiber group by controlling a peak power of the pulse light output from the optical modulator. It may be controlled.
  • the light amount control device makes fine adjustment of the light amount between each stage from the optical modulator. This is made possible by controlling the peak power of the output pulse light. Consequent The light quantity can be continuously controlled, and the light quantity of the output light can be made to coincide with the set light quantity regardless of the value of the set light quantity within a predetermined range. Therefore, more accurate exposure amount control becomes possible.
  • an exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; A light generator that has a light modulator that converts the light into light and outputs the light, and that generates a laser light of a single wavelength within a range from an infrared region to a visible region; and a pulse light generated by the light generator.
  • An optical amplifying unit including at least one stage fiber amplifier for amplifying light; and a light amount control device for controlling the amount of output light from the fiber amplifier by controlling the frequency of the pulse light output from the optical modulator.
  • a wavelength conversion unit that converts the wavelength of the laser light output from the optical amplification unit and outputs ultraviolet light that is a harmonic of the laser light; and converts the ultraviolet light output from the wavelength conversion unit to the ultraviolet light.
  • the illumination light for exposure An illumination optical system for illuminating the mask.
  • the mask is illuminated using the ultraviolet light output from the wavelength conversion unit by the illumination optical system as illumination light for exposure, and the pattern formed on the mask is transferred onto the substrate.
  • the light amount control device can control the light amount of the ultraviolet light applied to the mask in response to a necessary request, so that the required exposure amount control can be realized as a result.
  • the light amount control device further controls the light amount of the output light from the optical amplifying unit by controlling a peak power of the pulse light output from the optical modulator. It is good.
  • the present invention provides an exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; A light generator that has a light modulator that converts the light into pulsed light and outputs the light, and that generates a single-wavelength laser light within a range from an infrared region to a visible region; An optical amplifying unit including at least one fiber amplifier for amplifying the pulse light generated by the unit; and an output light from the optical amplifying unit by controlling a peak power of the pulse light output from the optical modulator.
  • a light amount control device that controls the light amount of the laser light; a wavelength conversion unit that converts the wavelength of the laser light output from the optical amplification unit and outputs ultraviolet light that is a harmonic of the laser light; An illumination optical system that illuminates the mask with the ultraviolet light output as illumination light for exposure.
  • the mask is illuminated using the ultraviolet light output from the wavelength conversion unit by the illumination optical system as illumination light for exposure, and the pattern formed on the mask is transferred onto the substrate.
  • the light amount control device can control the light amount of the ultraviolet light applied to the mask in response to a necessary request, so that the required exposure amount control can be realized as a result.
  • the present invention provides an exposure apparatus that repeatedly transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; and a pulse light that emits light from the light source.
  • a light generator having an optical modulator for converting the pulse light into light; an optical amplifier including at least one fiber amplifier for amplifying the pulse light generated by the light generator;
  • When exposing the substrate through the mask at least one of the frequency and peak power of the pulse light is transmitted through the optical modulator in accordance with the position of the exposure target area on the substrate.
  • a control device for controlling.
  • the light generator generates pulsed light by converting light of a single wavelength generated by the light source into pulsed light by an optical modulator, and the pulsed light is converted into an optical amplifier including a fiber amplifier. Is amplified by Then, the controller irradiates the mask with the amplified pulsed light, and when exposing the substrate through the mask, through the optical modulator according to the position of the exposure target area on the substrate. At least one of the frequency and peak power of the pulsed light is controlled, thereby irradiating the mask. The amount of light that is emitted, and thus the amount of exposure of the substrate, is controlled with high precision. Therefore, according to the present invention, it is possible to always appropriately control the exposure amount irrespective of the position of the exposure target area on the substrate, and it is possible to accurately transfer the mask pattern onto the substrate.
  • the “exposure target area” is a concept including both shot areas when there are a plurality of shot areas to be exposed on the substrate, and different areas within each shot area. Therefore, according to the present invention, in a so-called stepper (including a scanning stepper), a process variation in each shot area on a substrate is corrected, and a line width uniformity in one shot area in a scanning exposure apparatus is improved. Is possible.
  • an exposure apparatus for transferring a pattern formed on a mask onto a substrate, comprising: a light source for generating light of a single wavelength; and light from the light source to pulse light.
  • a light generating section having an optical modulator for conversion; and a plurality of optical paths including at least one optical fiber amplifier for amplifying the pulsed light and arranged in parallel at an output stage of the light generating section.
  • An optical amplifier irradiating the mask with the pulsed light from the optical amplifier, and exposing the substrate through the mask, individually turning on / off the optical output from each optical path;
  • a control device for controlling the amount of pulsed light output from the optical amplifying unit.
  • the light generator generates pulsed light by converting light of a single wavelength generated by the light source into pulsed light by an optical modulator, and the pulsed light is converted into an optical amplifier including a fiber amplifier. Is amplified by Then, the controller irradiates the mask with the amplified pulsed light, and when exposing the substrate through the mask, individually turns on / off the light output from each light path, thereby performing optical amplification.
  • the amount of pulsed light output from the unit is controlled, whereby the amount of light applied to the mask and, consequently, the amount of exposure of the substrate is controlled stepwise over a wide range. Therefore, according to the present invention, the resist feeling for each substrate in an exposure apparatus that repeatedly exposes a plurality of substrates is provided. It is possible to control the exposure amount according to the difference in the degree and the like. Therefore, it is possible to transfer the mask pattern onto the substrate with the required accuracy without being affected by the resist sensitivity or the like.
  • control device may control at least one of the frequency and the peak power of the pulse light via the optical modulator according to the position of the exposure target area on the substrate as described above.
  • the light source generates a laser beam in an infrared region or a visible region, and a wavelength conversion unit that converts the wavelength of the pulse light amplified by the light amplification unit into ultraviolet light. May be further provided.
  • the present invention is an exposure apparatus that illuminates a mask with a laser beam and transfers a pattern of the mask onto a substrate, wherein the laser light source oscillating the laser beam;
  • a beam monitoring mechanism for monitoring optical characteristics of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength; and an absolute wavelength providing source for providing an absolute wavelength close to the set wavelength.
  • a light source device having a temperature dependency map comprising temperature measurement data of a center wavelength of the laser light oscillated from the laser light source and a detection reference wavelength of the beam monitoring mechanism.
  • a first control device for performing a set wavelength calibration for matching the detection reference wavelength to the set wavelength based on the temperature dependence map; and a control device for setting the wavelength of the laser beam emitted from the light source device to the set wavelength calibration.
  • a second control device for irradiating the mask with the laser beam and exposing the substrate through the mask while performing feedback control based on the monitoring result of the beam monitoring mechanism for which the radiation has been completed. This is the sixth exposure apparatus.
  • the absolute wavelength carrier for making the detection reference wavelength of the beam monitor mechanism substantially coincide with the absolute wavelength provided from the absolute wavelength providing source by the first control device.
  • a temperature dependency map stored in the storage device (consisting of measurement data of the temperature dependency of the center wavelength of the laser light emitted from the laser light source and the detection reference wavelength of the beam monitoring mechanism).
  • the set wavelength calibration for matching the wavelength to the set wavelength is performed. In this manner, the detection reference wavelength of the beam monitor mechanism after the absolute wavelength calibration can be made to coincide with the set wavelength by using the temperature dependence of the detection reference wavelength of the known beam monitor mechanism.
  • the second control device controls the wavelength of the laser beam emitted from the light source device based on the monitoring result of the beam monitor mechanism after the completion of the set wavelength calibration, and controls the laser beam while performing feedback control.
  • the substrate is exposed through the mask by irradiating the mask. Therefore, while performing wavelength stabilization control to ensure that the center wavelength of the laser beam is maintained at the predetermined set wavelength based on the monitoring result of the beam monitoring mechanism, the laser beam is irradiated onto the mask and is passed through the mask. Since the substrate can be exposed, it is possible to perform high-precision exposure with little influence of temperature fluctuation of the atmosphere.
  • the apparatus may further include a third control device for calculating a wavelength change amount for almost canceling the variation, and changing the set wavelength according to the wavelength change amount. If the physical quantities related to the installation environment of the projection optical system (pressure, temperature, humidity, etc.
  • the third control device determines whether exposure of the substrate is started.
  • a wavelength change amount for substantially canceling a change in the imaging characteristic of the projection optical system due to a change in the physical quantity from the standard state based on the measurement value of the environment sensor is calculated,
  • the set wavelength is changed according to the wavelength change amount.
  • various aberrations of the projection optical system are corrected at the same time, and the second controller reliably uses the beam monitor mechanism to set the center wavelength of the laser beam to the predetermined set wavelength based on the changed set wavelength.
  • the laser beam is applied to the mask while performing wavelength stabilization control to maintain the laser beam.
  • the laser light emitted from the mask is projected on the substrate by the projection optical system, and the substrate is exposed.
  • exposure can be performed with high accuracy in a state where there is no change in physical quantity related to environmental conditions (that is, a state in which the change in imaging characteristics is offset). .
  • the atmospheric pressure in the standard state may be arbitrary, but for example, the optical performance of the projection optical system (including the imaging characteristics of the projection optical system) is best. It is desirable that the atmospheric pressure be a reference when the adjustment is made. In this case, the fluctuation amount of the optical performance of the projection optical system and the like becomes zero at the standard atmospheric pressure.
  • the standard atmospheric pressure is often set to the average atmospheric pressure of the delivery destination (factory, etc.) where the exposure apparatus is installed. Therefore, if there is an elevation difference between the assembly site where the exposure equipment is manufactured and the delivery destination (relocation location) where the exposure equipment is installed, for example, a projection optical system is installed under standard atmospheric pressure (such as average atmospheric pressure).
  • the exposure wavelength is shifted by the wavelength corresponding to the elevation difference, and then the projection optical system is adjusted.At the relocation site, the wavelength is returned to the exposure wavelength, or On the ground, the projection optical system is adjusted under the exposure wavelength, and the exposure wavelength is shifted so that the altitude difference is offset at the relocation site.
  • the above “atmospheric pressure” is the pressure of the gas around the projection optical system.
  • the present invention for example, changing the wavelength of the illumination light by the projection optical system and changing the installation environment (pressure, temperature, humidity, etc. of the surrounding gas) of the projection optical system. Making use of the fact that changing is substantially equivalent.
  • the type of the glass material of the refraction element of the projection optical system is single, the equivalence is completely established, and even when there are a plurality of types of glass materials, the equivalence is almost satisfied. Therefore, when only the wavelength of the illuminating light is changed by using the change characteristic of the refractive index of the projection optical system (particularly the refractive element) with respect to the installation environment, when the installation environment of the projection optical system is substantially changed. Can be realized.
  • the predetermined timing may be timing each time exposure of a predetermined number of substrates is completed, may be timing each time exposure of one shot on the substrate is completed, or may be a change in exposure conditions. May be the timing of each time.
  • the predetermined number may be one or may be a number corresponding to one lot.
  • the change of the exposure condition includes not only the change of the illumination condition but also all the cases where the condition regarding the exposure in a broad sense such as replacement of a mask is changed.
  • the predetermined timing may be a timing at which a physical quantity (or a change amount thereof) related to the environment obtained based on the measurement value of the environment sensor changes by a predetermined amount or more, or an optical system such as a projection optical system. It may be performed almost in real time according to the interval (for example, several S) at which the performance (or its variation) is calculated.
  • the predetermined timing may be a timing at every predetermined time.
  • the image processing apparatus further includes an imaging characteristic correction device that corrects an imaging characteristic of the projection optical system, wherein the imaging characteristic correction device changes the set wavelength each time the third control device changes the set wavelength.
  • the imaging characteristic variation may be corrected except for the variation in the imaging characteristic of the projection optical system, which is corrected by changing the set wavelength.
  • the “imaging characteristic change excluding the change in the imaging characteristic of the projection optical system corrected by the change in the set wavelength” includes the projection optical system caused by the change in the physical quantity due to the change in the set wavelength. If the change in the imaging characteristics of the projection optical system was not completely corrected, the change in the imaging characteristics of the projection optical system due to the change in the physical quantity was not corrected. The movement is also included.
  • the imaging characteristic correction device may correct the imaging characteristic change in consideration of the wavelength change of the laser light during the change of the set wavelength by the third control device. good.
  • the change of the set wavelength is performed at the above-mentioned predetermined timing. However, if the change interval of the set wavelength is long, the physical quantity fluctuates during that time, and the imaging characteristic correction device corrects the environmental fluctuation caused by this. It was decided to do so.
  • the sixth exposure apparatus of the present invention further includes an environment sensor that measures a physical quantity related to an environment near the projection optical system
  • the environment sensor may detect at least atmospheric pressure
  • the light source device includes: a fiber amplifier that amplifies laser light from the laser light source; and a nonlinear optical crystal that converts a wavelength of the amplified laser light into a wavelength in an ultraviolet region.
  • a wavelength converter may be further provided.
  • the laser light from the laser light source is amplified by the fiber amplifier, and the amplified laser light can be wavelength-converted into light in the ultraviolet region by the wavelength converter. Therefore, for example, even when the required light quantity is large, even if a small laser light source, for example, a solid-state laser such as a DFB semiconductor laser or a fiber laser is used, an energy beam of short wavelength and high energy is output. It becomes possible.
  • the present invention provides an exposure apparatus for exposing a substrate coated with a photosensitive agent by using an energy beam, comprising: a beam source for generating the energy beam; A wavelength changing device for changing the wavelength of the energy beam; and when the wavelength is changed by the wavelength changing device, the wavelength changing device is provided to the substrate in accordance with an amount of change in the sensitivity characteristic of the photosensitive agent accompanying the wavelength change. And a light exposure control device for controlling the integrated light exposure.
  • the change amount of the sensitivity characteristic of the photosensitive agent on the substrate caused by the change of the wavelength by the exposure amount control device.
  • the integrated exposure amount given to the substrate is controlled in accordance with.
  • the exposure amount control device can control the integrated exposure amount given to the substrate according to the amount of change in the sensitivity characteristic of the photosensitive agent caused by the wavelength change. Therefore, accurate exposure can be performed without being affected by changes in the sensitivity characteristics of the photosensitive agent.
  • the present invention is an exposure apparatus for transferring a predetermined pattern onto a substrate by irradiating the substrate with an exposure beam, wherein the light has a wavelength of any one of an infrared region and a visible region.
  • An eighth exposure apparatus comprising: a wavelength converter that emits light; and an optical system that irradiates the substrate with light emitted from the wavelength converter as the exposure beam.
  • a plurality of optical fibers, a polarization adjusting device, and a wavelength converter can efficiently generate ultraviolet light suitable for transfer of a fine pattern, and the ultraviolet light is converted into an exposure beam by the optical system as a substrate.
  • the predetermined pattern can be efficiently transferred to the substrate.
  • the present invention relates to an exposure apparatus that forms a predetermined pattern by irradiating exposure light to a substrate, wherein the exposure apparatus includes a phosphate glass to which a rare earth element is added and a bismuth oxide glass.
  • An optical amplifier that amplifies the incident light; a wavelength converter that converts the wavelength of the light emitted from the optical amplifier; and an optical amplifier that converts the light emitted from the wavelength converter.
  • a ninth exposure apparatus comprising: an optical system that irradiates the substrate as exposure light.
  • the optical waveguide member may be an optical fiber having a core for guiding light and a clad provided around the core.
  • the wavelength converter may generate the exposure light having a wavelength of 200 nm or less.
  • the exposure of the substrate with high accuracy can be performed efficiently by generating the exposure light having a wavelength of 200 nm or less, which has a small spread of the wavelength spectrum, from the wavelength converter.
  • a fine pattern corresponding to a short wavelength of less than 100 nm can be accurately formed on a substrate.
  • the ninth exposure apparatus of the present invention has a mask on which a predetermined pattern is formed, and when exposing a substrate via an optical system, a mask having substantially the same wavelength as the exposure light is used. By using the light generated by the wavelength converter in the position detection, it is possible to efficiently supply the position detection light.
  • the present invention relates to an exposure method for repeatedly transferring a pattern formed on a mask onto a substrate, and a first step of amplifying the pulsed light at least once using a fiber amplifier; Irradiating the mask with the amplified pulsed light A second step of exposing the exposure target area on the substrate via the mask; and, prior to the processing of the first step, converting a laser beam from a light source into the pulsed light, and exposing the exposure target area. A third step of controlling at least one of the frequency and peak power of the pulsed light according to the position on the substrate.
  • the pulsed light is amplified at least once by using a fiber amplifier, the amplified pulsed light is irradiated on a mask, and a region to be exposed on the substrate is exposed through the mask.
  • the laser light from the light source is converted into the pulsed light, and the frequency and the peak power of the pulsed light are determined according to the position of the exposure target area on the substrate. Control at least one of Therefore, when irradiating the mask with the pulse light and exposing the exposure target area on the substrate through the mask, the exposure is performed in a state where the exposure amount is adjusted according to the position of the exposure target area on the substrate. Will be Therefore, according to the present invention, it is possible to always appropriately control the exposure amount regardless of the position of the exposure target area on the substrate, and it is possible to transfer the mask pattern onto the substrate with high accuracy.
  • the “exposure target area” is a concept including both shot areas when there are a plurality of shot areas to be exposed on the substrate, and different areas within each shot area. Therefore, according to the present invention, in a so-called stepper (including a scanning stepper), a process variation in each shot area on a substrate is corrected, and a line width uniformity in one shot area in a scanning exposure apparatus is improved. Is possible.
  • the pulsed light may be amplified using only the selected fiber amplifier.
  • the exposure amount can be controlled stepwise in a wide dynamic range, at least one of the frequency and the peak power of the pulsed light is controlled according to the position of the exposure target area on the substrate.
  • the exposure control over a wider range can be performed with high accuracy.
  • the light source generates a laser light in an infrared region or a visible region, and wavelength-converts the amplified pulse light to ultraviolet light before the pulse light is applied to the mask.
  • the method may further include a fourth step.
  • the present invention provides an exposure method for exposing a substrate with a laser beam to form a predetermined pattern on the substrate, wherein the wavelength of the laser light is detected prior to the start of exposure.
  • the laser light A second step of repeatedly exposing a substrate with the laser light while controlling the wavelength of the laser light from a source.
  • the detection reference wavelength of the wavelength detection device after the absolute wavelength calibration is set to the set wavelength using the temperature dependence of the detection reference wavelength of the wavelength detection device measured in advance. Therefore, the detection reference wavelength of the wavelength detection device is always accurately set to the set wavelength.
  • the substrate is repeatedly exposed to the laser light while controlling the wavelength of the laser light from the laser light source based on the detection result of the wavelength detection device in which the detection reference wavelength is set to the set wavelength. . Therefore, according to the present invention, even if the temperature or the like of the atmosphere of the wavelength detecting device fluctuates, it is not affected.
  • Wavelength stabilization control that accurately sets the detection reference wavelength of the wavelength detector to the set wavelength without receiving it, and uses that wavelength detector to ensure that the center wavelength of the laser beam is maintained at the predetermined set wavelength. Since the substrate is repeatedly exposed to laser light while performing the process, high-precision exposure with little influence of temperature fluctuation of the atmosphere can be performed.
  • a third step of changing the set wavelength in order to cancel a change in optical performance of the optical system is further performed. May be included.
  • the substrate is controlled while performing wavelength stabilization control using a wavelength detector to ensure that the center wavelength of the laser beam is maintained at the predetermined set wavelength, using the changed set wavelength as a reference. Exposure can be repeated with laser light. As a result, exposure can be performed with high accuracy in a state where the fluctuation of the atmospheric pressure does not exist (that is, the fluctuation of the optical performance is offset).
  • the present invention provides a method for manufacturing an exposure apparatus for irradiating a substrate with an exposure light through an optical system to form a predetermined pattern, the method comprising adjusting the characteristics of the optical system.
  • a sixth aspect of the present invention is a method for manufacturing an exposure apparatus, wherein the method is performed using light having a wavelength belonging to a wavelength band having a predetermined width including the wavelength of the exposure light generated by the light source apparatus. According to this, it is possible to accurately and easily adjust the characteristics of the optical system through which the exposure light passes during the exposure.
  • the present invention is a device manufacturing method using the exposure method of the present invention or the exposure apparatus of the present invention, and can be said to be a device manufactured by the manufacturing method.
  • FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to one embodiment of the present invention.
  • FIG. 2 is a block diagram showing an internal configuration of the light source device of FIG. 1 together with a main control device.
  • FIG. 3 is a diagram schematically showing a configuration of the optical amplifier of FIG.
  • FIG. 4 is a diagram showing a cross-section of a bundle-one fiber formed by bundling the output ends of the final-stage fiber amplifier constituting the optical amplification unit.
  • FIG. 5 is a diagram schematically illustrating a fiber amplifier constituting the optical amplification unit in FIG. 2 and a peripheral portion thereof together with a part of a wavelength conversion unit.
  • Figure 6A shows a bundle—the fundamental wave of 1.544 tm emitted from the output end of fiber 173 is converted to an 8th harmonic using a nonlinear optical crystal.
  • Fig. 6B shows an example of the configuration of a wavelength conversion unit that generates 3 nm ultraviolet light.
  • Fig. 6B shows the fundamental wave of 1.57 m emitted from the output end of the bundle fiber 173.
  • FIG. 4 is a diagram showing a configuration example of a wavelength conversion unit that converts a wavelength into a 10th harmonic using a crystal and generates ultraviolet light of 157 nm.
  • FIG. 7 is a diagram for explaining a modified example, and is a diagram showing another configuration example of the optical amplifying unit.
  • FIG. 8 is a flowchart for explaining an embodiment of the device manufacturing method according to the present invention.
  • FIG. 9 is a flowchart showing the processing in step 204 of FIG. BEST MODE FOR CARRYING OUT THE INVENTION
  • FIG. 1 shows a schematic configuration of an exposure apparatus 10 according to one embodiment including a light source device according to the present invention.
  • the exposure apparatus 10 is a step-and-scan type scanning exposure apparatus.
  • the exposure apparatus 10 includes an illumination system including a light source device 16 and an illumination optical system 12, and a reticle as a mask illuminated by exposure illumination light (hereinafter, referred to as “exposure light”) IL from the illumination system.
  • exposure light exposure illumination light
  • a reticle stage RST holding R, a projection optical system PL that projects the exposure light IL emitted from the reticle R onto the wafer W as a substrate, and a Z tilt stage 58 as a substrate stage holding the wafer W are mounted.
  • the light source device 1 6 is, for example, a wavelength 1 9 3 nm (A r F excimer laser beam substantially the same wavelength) ultraviolet pulse (approximately the same wavelength as the F 2 laser beam) ultraviolet pulse light, or wavelength 1 5 7 nm of This is a harmonic generator that outputs light.
  • the light source device 16 has at least a part thereof (for example, a wavelength conversion section described later), the illumination optical system 12, the reticle stage RST, the projection optical system PL, the Z tilt stage 58, and the XY stage 1 4 and an exposure apparatus main body including a main body column (not shown) on which these components are mounted, as well as an environmental instrument and chamber (hereinafter referred to as “chamber”) whose temperature, pressure, humidity, etc.
  • FIG. 2 is a block diagram showing the internal configuration of the light source device 16 together with a main control device 50 that controls the entire device.
  • the light source device 16 includes a light source section 16 A including a laser light source as a light source, a laser control device 16 B, a light amount control device 16 C, and a polarization adjusting device 16 D. Etc. are provided.
  • the light source section 16A includes a pulse light generation section 160 as a light generation section, an optical amplification section 161, a quarter-wave plate 162 as a polarization direction conversion device, and a wavelength conversion section. It is configured to include a wavelength conversion section 163, a beam monitoring mechanism 164, an absorption cell 165, and the like.
  • the pulse light generator 160 includes a laser light source 160 A, optical couplers BS 1 and BS 2, an optical isolator 160 B, and an electro-optical modulator (hereinafter referred to as ⁇ ) 160 C as an optical modulator. Have.
  • each element between the laser light source 16 OA and the wavelength conversion unit 163 is optically connected by an optical fiber.
  • the laser light source 16 OA here, a single-wavelength oscillation laser, for example, an oscillation wavelength of 1.544 / m, continuous wave output (hereinafter referred to as “CW output”) 20 mW of InGaAsP, DFB Semiconductor lasers are used.
  • the laser light source 160A is also referred to as "DFB semiconductor laser 160A" as appropriate.
  • a DFB semiconductor laser is one in which a diffraction grating is built up in a semiconductor laser instead of a flat-peripheral resonator with low longitudinal mode selectivity. It is configured to oscillate and is called a distributed feedback (DFB) laser. Since such a laser basically oscillates in a single longitudinal mode, its oscillation spectrum line width can be suppressed to 0.01 pm or less.
  • the DFB semiconductor laser is usually provided on a heat sink, and these are housed in a housing.
  • a temperature controller for example, a Peltier element
  • the laser controller 16 B By controlling the wavelength, the oscillation wavelength can be controlled (adjusted).
  • the temperature dependence of the oscillation wavelength of the DFB semiconductor laser 160 A is measured in advance, and the measurement result is provided in the main controller 50 as a temperature dependence map. It is stored (stored) as a table shape, a conversion function, or a conversion coefficient in a memory 51 as a storage device.
  • the oscillation wavelength of the DFB semiconductor laser 16 OA is about 0.1 nm / ° C. It has temperature dependence. Therefore, for example, if the temperature of the DFB semiconductor laser is changed by 1 ° C, the wavelength changes by 0.1 nm in the fundamental wave (1544 nm), and the wavelength changes in the eighth harmonic (193 nm). The wavelength changes by 0.0125 nm, and the wavelength changes by 0.01 nm at the 10th harmonic (157 nm).
  • the wavelength of the exposure illumination light (pulse light) can be changed by about ⁇ 20 pm with respect to the center wavelength. Therefore, the temperature of the DFB semiconductor laser 160 A is ⁇ 1.6 at the eighth harmonic. In the case of C and 10th harmonic, it may be changed by about ⁇ 2 ° C.
  • the laser light source 160A is not limited to a semiconductor laser such as a DFB semiconductor laser, but may be a ytterbium (Yb) -doped fiber laser having an oscillation wavelength of around 990 nm, for example.
  • a semiconductor laser such as a DFB semiconductor laser
  • Yb ytterbium
  • the optical couplers B S1 and B S2 those having a transmittance of about 97% are used. For this reason, the laser light from the DFB semiconductor laser 160 A is split by the optical coupler BS 1, and about 97% of the laser light is incident on the next-stage optical coupler BS 2, and the remaining about 3% is the beam monitor mechanism 164. Incident on.
  • the laser light incident on the optical coupler BS 2 is demultiplexed by the optical coupler BS 2, and about 97% of the laser light travels toward the next-stage optical isolator 160 B, and the remaining about 3% is absorbed by the absorption cell 165. To be incident on.
  • the beam monitor mechanism 164, absorption cell 165, etc. will be described later in further detail.
  • the optical isolator 160B is a device for passing only light in the direction from the optical coupler BS2 to the EOM 160C and blocking the light in the opposite direction.
  • the optical isolator 160B prevents a change in the oscillation mode of the DFB semiconductor laser 160A and the generation of noise due to the reflected light (return light).
  • the EOM 160C is for converting laser light (CW light (continuous light)) that has passed through the optical isolator 160B into pulsed light.
  • EOM 1 as 60 C
  • An electro-optic modulator for example, a two-electrode type modulator
  • the EOM 160 C outputs a pulse light modulated in synchronization with a voltage pulse applied from the light amount control device 16 C.
  • the laser light oscillated by the DFB semiconductor laser 16 OA by the EOM 160 C is modulated into pulse light with a pulse width of 1 ns and a repetition frequency of 100 kHz (pulse period of about 10 s).
  • the peak output of the pulse light output from the EOM 160 C is 2 OmW, and the average output is 2.
  • the insertion loss is present, for example, if the loss is 13 dB, the peak output of the pulsed light is 1 OmW and the average output is 1 OmW. W.
  • the repetition frequency is set to about 100 kHz or higher, a decrease in the amplification factor due to the influence of ASE (Amplified Spontaneous Emission) noise can be prevented in the fiber amplifier described later. This is desirable.
  • the output light can be pulse-oscillated by controlling the current.
  • the pulse light can be generated by using the current control of the DFB semiconductor laser 160A and the EOM 160C together.
  • a pulse light having a pulse width of, for example, about 10 to 20 ns is oscillated by current control of the DFB semiconductor laser 160A, and only a part of the pulse light is cut out from the pulse light by the EOM 160C.
  • the pulse width is modulated to 1 ns.
  • AOM acousto-optic light modulator
  • the optical amplifying unit 161 amplifies the pulse light from the EOM 160 C, and here includes a plurality of fiber amplifiers.
  • FIG. 3 shows an example of the configuration of the optical amplifier 161, together with the EON / M 60C.
  • the optical amplifying unit 161 includes a branch and delay unit 167 having a total of 128 channels from channel 0 to channel 127, and a channel 0 of the branch and delay unit 167.
  • channel 1 27 total 1 28 channel of the respective output stage connected fiber amplifiers 1 68 from ⁇ 1 68 128, these fiber amplifiers 1 68, and 1 68 narrowband filter 1 69 to each of 128 ⁇ 1 6 9 128 and the optical isolator 1 70, and 1 70 128 in the final stage which is connected via respective file I bus amplifier 1 7 1 ⁇ -! 7 1 128 etc.
  • the branching and delay unit 167 has a total of 128 channels, and outputs a predetermined delay time (here, 3 ns).
  • the branching and delay unit 167 is an erbium (Er) -doped fiber for amplifying the pulse light output from the EOM 160 C by 35 dB (3162 times).
  • the 0 to 31 channels of each of the above splitters flat waveguide 1 ⁇ 32 splitter
  • the pulse light output from the first-stage EDFA has a peak output of about 63 W and an average output of about 6.3 mW.
  • This pulse light is split in parallel into four outputs of channels 0 to 3 by a splitter (a flat waveguide 1 ⁇ 4 splitter), and the output light of each channel is given a delay corresponding to the above four optical fiber lengths.
  • the optical delay between adjacent channels at each first delay fiber exit is 96 ns.
  • channels 1 to 31 of the four splitters each have an optical fiber of 0.6 XN meter (where N is the channel number) (hereinafter referred to as “No. 2 called “delay fiber”).
  • No. 2 the delay fiber
  • a delay of 96 ns is given between the first to fourth blocks by the first delay fiber at the time of input of each block as described above. Therefore, the channel 0 output of the second block has a delay of 96 ns with respect to the channel 0 output of the first block, and the delay with the channel 31 of the first block is 3 ns. This is the same between the second and third blocks and the third and fourth blocks. As a result, a total of 128 channels of output ends, adjacent channels A pulse light with a delay of 3 ns between the pulses is obtained.
  • the mode field diameter of the optical fiber (hereinafter referred to as “mode diameter J”) is the same as that used in normal communication.
  • Erbium (Er) -doped fiber amplifier (EDFA) with a length of 5 to 6 m.
  • the output light from each channel of the delay unit 167 is provided by the fiber amplifier 168 n .
  • the excitation light source of the fiber amplifier 168 n will be described later.
  • the ASE light is converted to the fiber amplifier 17 1 n in the subsequent stage. In this case, it is possible to prevent the amplification gain of the laser light from being lowered by being incident on the laser beam, or to prevent the scattering of the laser light due to the propagation of the ASE noise.
  • the wavelength width of the ASE light is about several tens of nm, it is possible to cut the ASE light so that there is no practical problem even if a narrow band filter with a transmission wavelength width of about 100 pm is available at this time. it can.
  • the output wavelength of the DFB semiconductor laser 16 OA may be actively changed as described later. It is preferable to use a narrow-band filter having a transmission wavelength width (approximately equal to or greater than the variable width) according to (approximately pm).
  • the wavelength width of a laser device applied to an exposure device is set to about 1 pm or less.
  • Said fiber amplifier 1 7 1 ⁇ (n 1 , 2, ising, 1 28) as here, the light in order to avoid an increase in Supekubokuru width of amplified light due to the nonlinear effect in the optical fiber EDFAs with a large mode diameter, for example, 20 to 30 m, are used, which have fiber mode diameters wider than those used in normal communication (5 to 6 Atm).
  • the fiber amplifier 171 n further amplifies the optical output from each channel of the branch and delay unit 167 amplified by the above-described fiber amplifier 168.
  • the branch and delay unit 167 The average output of each channel is about 50 W, and the average output of all channels is about 6.3 mW, which is amplified by a total of 46 dB (40600 times) by two-stage fiber amplifiers 168 memoand 17. Then, at the output end of the optical path 172 n corresponding to each channel (the output end of the optical fiber constituting the fiber amplifier 171 n ), the peak output is 20 kW, the pulse width is 1 ns, and the pulse repetition frequency is 10 O Obtain 2 kHz, 2 W average power, and 256 W average power on all channels. The pump light source of the fiber amplifier 17 will be described later.
  • Chikaratan out of the optical fibers constituting the output end of the optical path 1 72 n corresponding to each channel at the branch and delay unit 1 67, i.e. the fiber amplifier 1 7 1 n is bundled in a bundle shape And have a cross section as shown in Fig. 4.
  • a dollar fiber 1 173 is formed.
  • the bundle fiber 173 is formed using the output end of the final stage fiber amplifier 171 amortizas it is, but the undoped optical fiber is added to the final stage fiber amplifier 171 ⁇ . Can be combined to form a bundle-one fiber at its output end.
  • FIG. 5 schematically shows a fiber amplifier constituting the optical amplifying unit 161 and a peripheral portion thereof, together with a part of the wavelength converting unit 163.
  • a semiconductor laser 178 for pumping the first stage fiber amplifier 168 ⁇ is fiber-coupled to the fiber amplifier 168 ⁇ , and the output of the semiconductor laser 178 is coupled to a wavelength division multiplexing device (Wavel The signal is input to a fiber amplifier dope fiber through an intensity division multiplexer (WDM) 179 to excite the doped fiber.
  • WDM intensity division multiplexer
  • the fiber amplifier 17 1 n having a large mode diameter uses a semiconductor laser 17 4 as a pumping light source for pumping the above-described fiber amplifier dope having a large mode diameter, and a fiber amplifier dope.
  • the fiber is coupled to a large-diameter fiber that matches the diameter of the fiber, and the output of this semiconductor laser 174 is input to a doped * fiber for optical amplifier using 0 1 ⁇ 1 176, and the doped fiber To excite.
  • the laser light amplified by the large-mode diameter fiber (fiber amplifier) 17 1 issues the wavelength conversion section 16 3, where it is converted into an ultraviolet laser light. Configuration 3 and the like will be described later.
  • Large mode diameter fibers (fiber amplifier) 1 7 1 n les to be amplified propagating Ichizako (signal) is desirably mainly the fundamental mode, which is single-mode or mode order lower multimode In a fiber, this can be mainly achieved by selectively exciting the basic mode.
  • the present embodiment four high-power semiconductor lasers coupled to a large-mode diameter fiber are fiber-coupled from the front and four from the rear.
  • an optical fiber having a double clad structure with a double clad structure is used as the optical amplification dope fiber. It is desirable to use.
  • the pumping semiconductor laser light is introduced into the inner clad of the double clad by WDM176.
  • the semiconductor lasers 178 and 174 are controlled by a light amount control device 16C.
  • the fiber amplifier 1 6 8 n, 1 7 1 " is provided as the optical fiber constituting the optical path 1 7 2 n described above, the difference between the gain of each fiber amplifier in each channel the variation of the optical output.
  • a portion of output fiber amplifier of each channel (1 6 8 n, 1 7 1 n) is branched, provided each branch ends
  • the photoelectric conversion is performed by the photoelectric conversion elements 180 and 181, respectively.
  • the output signals of these photoelectric conversion elements 180 and 181 are supplied to the light quantity control device 16C. It has become.
  • the drive current of each pumping semiconductor laser (178, 174) is controlled so that the optical output from each fiber amplifier is constant (that is, balanced) in each amplification stage. Feedback control.
  • the light split by the beam splitter in the middle of the wavelength conversion section 163 is photoelectrically converted by the photoelectric conversion element 182, and the photoelectric conversion element
  • the output signal of 18 2 is supplied to the light quantity control device 16 C.
  • the output of this photoelectric conversion element 18 2 The light intensity in the wavelength conversion unit 163 is monitored based on the signal, and at least one of the pumping semiconductor lasers 178 and 174 is controlled so that the light output from the wavelength conversion unit 163 becomes a predetermined light output.
  • One drive current is feedback-controlled.
  • the amplification factor of the fiber amplifier of each channel is fixed at each amplification stage, so that there is no uneven load between the fiber amplifiers and the light intensity is uniform as a whole. Is obtained.
  • a predetermined light intensity is fed back to each amplification stage, and a desired ultraviolet light output can be stably obtained.
  • the light amount control device 16C will be described later in further detail.
  • the wavelength conversion section 163 includes a plurality of nonlinear optical crystals, and converts the amplified pulse light (light having a wavelength of 1.544 ⁇ ⁇ ) into an 8th harmonic or a 10th harmonic thereof. conversion to, for generating a pulse ultraviolet light a r F excimer laser with the same output wavelength (1 9 3 nm) or an F 2 laser with the same output wavelength (1 5 7 nm).
  • FIG. 6A and FIG. 6B show a configuration example of the wavelength conversion unit 163.
  • a specific example of the wavelength converter 163 will be described based on these drawings.
  • Figure 6A shows a bundle—a 1.54 4 xm fundamental wave emitted from the output end of fiber 173 is converted to an 8th harmonic (harmonic) using a nonlinear optical crystal.
  • FIG. 6 B performs harmonic generation 1 0 harmonic by using a nonlinear optical crystal a fundamental wave having a wavelength 1. 5 7 m emitted from the output end of the bundle one fiber 1 7 3, F 2 laser
  • the above-described linear polarization by the quarter-wave plate 162 is performed so that the nonlinear optical crystal 533 has a polarization direction in which the second harmonic is generated most efficiently.
  • the setting of the polarization direction of such linearly polarized light is performed by adjusting the direction of the optical axis of the quarter-wave plate 162.
  • L i B 3 0 5 L BO
  • NC PM Non-Critical Phase Matching
  • the fundamental wave transmitted through the non-linear optical crystal 533 without wavelength conversion and the second harmonic generated by the wavelength conversion are delayed by a half-wavelength and a one-wavelength in the next-stage wave plate 534, respectively. Only the wave rotates its polarization direction by 90 degrees and enters the second-stage nonlinear optical crystal 536.
  • An LBO crystal is used as the second-stage nonlinear optical crystal 536, and the LBO crystal is used in the NC PM having a temperature different from that of the first-stage nonlinear optical crystal (LB0 crystal) 533.
  • a third harmonic (wavelength) is generated by sum frequency generation from the second harmonic generated in the first-stage nonlinear optical crystal 533 and the fundamental wave transmitted through the nonlinear optical crystal 533 without wavelength conversion. 5 15 nm).
  • the third harmonic obtained by the nonlinear optical crystal 536 and the fundamental wave and the second harmonic transmitted through the nonlinear optical crystal 536 without wavelength conversion are separated by the dichroic mirror 537.
  • the third harmonic reflected by the light passes through the condenser lens 540 and the dichroic mirror 543 and enters the fourth-stage nonlinear optical crystal 545.
  • the fundamental wave and the second harmonic transmitted through the dichroic mirror 537 pass through the condenser lens 538 and enter the third-stage nonlinear optical crystal 539.
  • the third-stage nonlinear optical crystal 539 an LBO crystal is used as the third-stage nonlinear optical crystal 539.
  • the fundamental wave passes through the LBO crystal without wavelength conversion, and the second harmonic is generated by the second harmonic generation in the LBO crystal. It is converted to a harmonic (wavelength 386 nm).
  • the fourth harmonic obtained by the nonlinear optical crystal 539 and the fundamental wave transmitted therethrough are separated by the dichroic mirror -54 1, and the fundamental wave transmitted there passes through the condenser lens 544 and becomes dichroic ⁇
  • the light is reflected by the mirror 546 and enters the fifth-stage nonlinear optical crystal 548.
  • the fourth harmonic reflected by the dichroic mirror 54 1 passes through the condenser lens 542 and reaches the dichroic mirror 543, where it is coaxial with the third harmonic reflected by the dichroic mirror 537.
  • the synthesized light enters the fourth stage nonlinear optical crystal 545.
  • the nonlinear optical crystal 545 in the fourth stage, / 3- B a B 2 0 4 (B BO) crystal is used, the third harmonic and 7 harmonic (wavelength 22 1 nm by sum frequency generation and a fourth harmonic ).
  • the 7th harmonic obtained by the nonlinear optical crystal 545 passes through the condenser lens 547, and is coaxially synthesized with the fundamental wave transmitted through the dichroic mirror 541 by the dichroic mirror 546.
  • the light enters the nonlinear optical crystal 548.
  • An LBO crystal is used as the fifth-stage nonlinear optical crystal 548, and an eighth harmonic (wavelength: 193 nm) is obtained from the fundamental wave and the seventh harmonic by generating a sum frequency.
  • a lens 540 that condenses the third harmonic is used.
  • the lens 542 that collects the fourth harmonic can be placed in separate optical paths.
  • the cross-section of the fourth harmonic generated by the third-stage nonlinear optical crystal 539 has an elliptical shape due to the walk-of-f phenomenon. For this reason, in order to obtain good conversion efficiency in the fourth-stage nonlinear optical crystal 545, it is desirable to perform beam shaping of its fourth harmonic.
  • the condenser lenses 540 and 542 are arranged in separate optical paths, for example, a pair of cylindrical lenses can be used as the lens 542, thereby facilitating beam shaping of the fourth harmonic. It becomes possible. For this reason, it is possible to improve the conversion efficiency by improving the overlap with the third harmonic in the fourth-stage nonlinear optical crystal (BBO crystal) 545.
  • BBO crystal nonlinear optical crystal
  • the lens 544 for condensing the fundamental wave incident on the fifth-stage nonlinear optical crystal 548 and the lens 545 for condensing the seventh harmonic can be placed in different optical paths.
  • the seventh harmonic generated by the fourth-stage nonlinear optical crystal 545 has an elliptical cross-sectional shape due to the walk-of-f phenomenon. Therefore, in order to obtain good conversion efficiency in the fifth-stage nonlinear optical crystal 548, it is preferable to perform beam shaping of the seventh harmonic.
  • the condenser lenses 544 and 544 can be arranged in separate optical paths, so that, for example, a pair of cylindrical lenses can be used as the lens 544, so that beam shaping of the seventh harmonic can be easily performed. Can be performed. For this reason, it is possible to improve the conversion efficiency by improving the overlap with the fundamental wave in the fifth-stage nonlinear optical crystal (LB0 crystal) 548.
  • Non-linear optics are used to reflect the third harmonic reflected by the mirror 537 and the second harmonic generated from the nonlinear optical crystal 536 and transmitted through the dichroic mirror 537. Any configuration is possible as long as the two optical path lengths between the nonlinear optical crystals 536 and 545 are equal so that the fourth harmonic obtained by wavelength conversion by the crystal 539 simultaneously enters the nonlinear optical crystal 545. No problem. This is the same between the third-stage nonlinear optical crystal 539 and the fifth-stage nonlinear optical crystal 548. According to the experiment performed by the inventor, in the case of FIG.
  • the average output of the eighth harmonic (wavelength 193 nm) per channel was 45.9 mW. Therefore, the average output from the bundle including all 128 channels is 5.9 W, and it is possible to provide ultraviolet light with a wavelength of 193 nm, which has a sufficient output as a light source for an exposure apparatus.
  • LB0 crystals which are readily available as high-quality crystals on the market, are currently used to generate the eighth harmonic (193 nm).
  • This LBO crystal has an extremely small absorption coefficient of 193 nm ultraviolet light, and is advantageous in terms of durability since optical damage of the crystal is not a problem.
  • the LB0 crystal In the generation part of the eighth harmonic (for example, the wavelength of 193 nm), the LB0 crystal is used after being phase-matched. However, since the phase-matching angle is large, the effective nonlinear optical constant (d eff) becomes small. Therefore, it is preferable to provide a temperature control mechanism for the LBO crystal and use the LBO crystal at a high temperature. As a result, the phase matching angle can be reduced, that is, the constant (deff) can be increased, and the efficiency of generating the eighth harmonic can be improved.
  • the fundamental wave (wavelength 1.57 m) ⁇ the second harmonic wave (wavelength 785 nm) ⁇ the fourth harmonic wave (wavelength 392.5 nm) ⁇ the eighth harmonic wave (wavelength 196.25 nm) ) ⁇
  • the wavelength is converted in the order of the 10th harmonic (wavelength: 157 nm).
  • the second harmonic generation of the wavelength incident on each wavelength conversion stage is performed in each wavelength conversion stage from the second harmonic generation to the eighth harmonic generation.
  • an LB0 crystal is used as a nonlinear optical crystal 602 that generates a second harmonic by generating a second harmonic from a fundamental wave.
  • Nonlinear optical coupling that generates fourth harmonic by second harmonic generation LBO crystal is used as crystal 604.
  • SBBO S r 2 B e 2 B 2 0 7
  • the SBB0 crystal is used for the nonlinear optical crystal 611 that generates a 10th harmonic (wavelength: 157 nm) by sum frequency generation from the harmonic.
  • the second harmonic generated from the nonlinear optical crystal 602 enters the nonlinear optical crystal 604 through the condenser lens 603, and the nonlinear optical crystal 604 has the above-described fourth harmonic and wavelength. Generates second harmonics that are not converted.
  • the second harmonic transmitted through the dichroic * mirror 605 passes through the condenser lens 606, is reflected by the dichroic mirror 607, and enters the nonlinear optical crystal 611.
  • the fourth harmonic reflected by the dich aperture mirror 605 enters the nonlinear optical crystal 609 through the condenser lens 608, and the eighth harmonic generated here is collected.
  • Optical lens 610 and dichroic ⁇ It enters the nonlinear optical crystal 611 through the mirror 607. Further, the nonlinear optical crystal 611 generates a 10th harmonic (wavelength: 157 nm) from the second harmonic and the eighth harmonic coaxially synthesized by the dichroic mirror 607 by generating a sum frequency.
  • the second harmonic and the fourth harmonic generated from the second-stage nonlinear optical crystal 604 are branched by the dichroic mirror 605 so that the second harmonic transmitted therethrough
  • the fourth harmonic is obtained by wavelength-converting the fourth harmonic with the nonlinear optical crystal 609, and is incident on the fourth-stage nonlinear optical crystal 611 through different optical paths
  • the dichroic 'Four non-linear optical crystals 62, 604, 609, and 611 may be arranged on the same optical axis without using the mirrors 605 and 607.
  • the fourth harmonic generated in the second-stage nonlinear optical crystal 604 has an elliptical cross-sectional shape due to the walk-of phenomenon.
  • the beam shape of the fourth harmonic wave which is the incident beam, is shaped and overlapped with the second harmonic wave It is desirable to improve the quality.
  • the condenser lenses 606 and 608 are placed on separate optical paths. Since the lenses can be arranged, for example, a cylindrical lens can be used as the lens 608, and beam shaping of the fourth harmonic can be easily performed. For this reason, it is possible to make the overlap with the second harmonic in the fourth-stage nonlinear optical crystal 6 11 1 good, and to increase the conversion efficiency.
  • the wavelength converters shown in FIGS. 6A and 6B are merely examples, and it goes without saying that the configuration of the wavelength converter of the present invention is not limited to this.
  • the beam monitor mechanism 164 is composed of a photoelectric conversion element such as a Fabry-Pero etalon (hereinafter also referred to as “etalon element j”) and a photoelectric conversion element such as a photodiode.
  • the light incident on the etalon element constituting the beam monitor mechanism 16 4 has a transmittance corresponding to the frequency difference between the resonance frequency of the etalon element and the frequency of the incident light.
  • An output signal of a photodiode or the like for detecting the transmitted light intensity is supplied to a laser controller 16 B.
  • the laser controller 16 B performs a predetermined signal processing on this signal.
  • the etalon element specifically, the center wavelength and the wavelength width of the incident light (spectral half width), etc.
  • the frequency characteristics of the transmitted light intensity generated by the ETA element are affected by the temperature and pressure of the atmosphere.
  • the resonance frequency (resonance wavelength) is temperature-dependent. Therefore, in order to accurately control the center wavelength of the laser light oscillated from the laser light source 16 OA based on the detection result of this etalon element, it is necessary to examine the temperature dependence of the resonance wavelength. is important.
  • the temperature dependence of the resonance wavelength is measured in advance, and the measurement result is attached to the main controller 50 as a temperature dependence map. It is stored in a memory 51 (see FIG. 1) as a storage device.
  • the temperature dependence map may be stored in the memory 51 in the form of a table, or may be stored as a function or a coefficient.
  • main controller 50 uses the temperature dependence map to determine the resonance wavelength at which the transmittance of the etalon element becomes maximum (detection reference wavelength) at the time of absolute wavelength calibration of beam monitor mechanism 164, which will be described later.
  • detection reference wavelength the resonance wavelength at which the transmittance of the etalon element becomes maximum
  • the output of the energy monitor constituting the beam monitor mechanism 164 is supplied to the main controller 50.
  • the main controller 50 detects the energy power of the laser beam based on the output of the energy monitor.
  • the DFB semiconductor laser 16 OA controls the amount of laser light oscillated by the DFB semiconductor laser 16 OA via the laser controller 16 B as necessary, or turns off the DFB semiconductor laser 16 OA.
  • normal light amount control exposure amount control
  • the light amount control device 16 C by controlling the peak power or frequency of the output pulse light of the EOM 160 C, or Since the output power of each fiber amplifier constituting the optical amplifying unit 16 1 is controlled by on / off control, when the energy power of the laser light fluctuates greatly for some reason, the main controller 50 is controlled by the laser controller 1. 6B will be controlled as described above.
  • the absorption cell 165 is an absolute wavelength source for the absolute wavelength calibration of the oscillation wavelength of the DFB semiconductor laser 16OA, that is, the absolute wavelength calibration of the beam monitor mechanism 164.
  • the absorption cell 165 uses a DFB semiconductor laser 160 A having an oscillation wavelength of 1.544 Atm as a laser light source, the absorption cell 165 has a wavelength band near this wavelength. Acetylene isotopes with dense absorption lines are used.
  • a fundamental wave and a fundamental wave are used as light for monitoring the wavelength of the laser light.
  • the above-described intermediate wave (second harmonic, third harmonic, fourth harmonic, etc.) of the wavelength conversion unit 163 or the light after wavelength conversion, the intermediate wave, etc. It is sufficient to use an absorption cell in which absorption lines exist densely in the above wavelength band.
  • an absorption cell in which absorption lines exist densely in the above wavelength band.
  • an iodine molecule having an absorption line in the vicinity of a wavelength of 50353111 to 530 nm is used as an absorption cell, and the iodine molecule is used.
  • the appropriate absorption line may be selected and its wavelength may be used as the absolute wavelength.
  • the absolute wavelength source is not limited to the absorption cell, and an absolute wavelength light source may be used.
  • the laser controller 16B Under the control of the main controller 50, the laser controller 16B detects the center wavelength and the wavelength width (spectral half width) of the laser beam based on the output of the beam monitor mechanism 164, The temperature control (and current control) of the DFB semiconductor laser 16 OA is performed by feedback control so that the center wavelength becomes a desired value (set wavelength). In this embodiment, the intensity of the DFB semiconductor laser 16 OA can be controlled in 0.001 ° C. units.
  • the laser controller 16B switches between the pulse output and the continuous output of the DFB semiconductor laser 160A according to the instruction from the main controller 50, and the output interval and pulse width at the time of the pulse output. Controls the oscillation of the DFB semiconductor laser 16 OA so as to compensate for the output fluctuation of the pulsed light. In this way, the laser controller 16B stabilizes the oscillation wavelength to control it at a constant wavelength, or fine-tunes the output wavelength. Conversely, the laser control device 16B may adjust the output wavelength by positively changing the oscillation wavelength of the DFB semiconductor laser 160A in accordance with an instruction from the main control device 50. This is described further below.
  • the temperature dependence of the oscillation wavelength of the DFB semiconductor laser 16 OA and the resonance wavelength (A res ) of the etalon element in the beam monitor mechanism 164 is measured in advance, and the measurement results are stored in the memory. 5 Memorized in 1.
  • the main controller 50 absorbs the laser light through the laser controller 16 B while the DFB semiconductor laser 16 OA is oscillated via the laser controller 16 B.
  • the absorption line of the wavelength (A ref ) closest to or matching the set wavelength (A set ) at which the transmittance of the cell 165 becomes the maximum is selected.
  • An instruction is given to the laser controller 16B to control the temperature of the etalon element in the beam monitor mechanism 164. That is, the resonance wavelength (A res ) of the etalon element is calibrated using the absolute wavelength ( ⁇ ref ).
  • a res is the detection reference wavelength of the etalon device matches the absolute wavelength (lambda " ⁇ ).
  • the main controller changes the oscillation wavelength of the DF ⁇ semiconductor laser 160 ⁇ through the laser controller 16 within a predetermined range. Is also good. In this way, even when the oscillation wavelength of the DF ⁇ semiconductor laser 16 OA is greatly deviated from the set wavelength at the start of the oscillation, the setting is such that the transmittance of the absorption cell 16 5 is quickly maximized. This makes it possible to select the absorption line at the wavelength (A rei ) closest to or coincident with the wavelength (A set ), so that the absolute wavelength calibration can be completed in a short time.
  • the main controller 50 uses the temperature-dependent data of the resonance wavelength (A res ) of the etalon element stored in the memory 51 to store the laser controller 1. 6 Control the temperature of the etalon element via B, and execute the setting wavelength calibration to set the resonance wavelength (A res ) of the etalon element to the set wavelength (A set ).
  • the etalon element The ringing wavelength (A res ), that is, the detection reference wavelength can be surely matched with the set wavelength.
  • the temperature of the DFB semiconductor laser 160 A is controlled by the laser controller 16 B based on the detected value of the etalon element for which the set wavelength calibration has been completed (the monitoring result of the beam monitor mechanism 164). Control and current control are performed by feedback control.
  • the reason why the laser controller 16 B controls not only the temperature of the DFB semiconductor laser 16 OA but also the supply current (drive current) is that the responsiveness is better with the current control. .
  • the occurrence (or image change) of the aberration of the projection optical system PL due to wavelength fluctuation or its fluctuation is prevented, and the image characteristic (optical characteristics such as image quality) changes during pattern transfer. Disappears.
  • Variations in the imaging characteristics (such as aberrations) of the projection optical system PL that occur depending on the situation can be offset, and the time required to start up the exposure apparatus at the delivery destination can be reduced.
  • variations in the aberration, projection magnification, and focal position of the projection optical system PL caused by irradiation of the exposure illumination light and changes in the atmospheric pressure. It is possible to cancel each other and transfer the pattern image onto the substrate in the best imaging state at all times.
  • the light amount control device 16C is provided with the photoelectric conversion elements 18 0 and 18 1 for detecting the optical outputs of the fiber amplifiers 16 68 n and 17 1 n in the optical amplification section 16 1.
  • the drive current of each pumping semiconductor laser (178, 174) is feedback-controlled to stabilize the gain of the fiber amplifier of each channel for each amplification stage.
  • the drive current of at least one of the semiconductor lasers for excitation 1778, 174 is determined.
  • Feedback control It has a function of feeding back a predetermined predetermined light intensity to each amplification stage and stabilizing a desired ultraviolet light output.
  • the light amount control device 16C also has the following functions.
  • the output of the fiber of each channel constituting the bundle 1 fiber 173, that is, the output of each optical path 172 n is individually turned off. Function to control the average light output of the entire bundle
  • the first function (Hereinafter referred to as "the first function" for convenience)
  • Output (output energy), that is, a function of controlling the intensity of output light from each optical path 17 2 n per unit time (hereinafter referred to as “second function” for convenience)
  • the light quantity control device 16C turns on / off the output of each optical path 1772 in the first function, and turns on / off the output from the fiber amplifier 17 1 ⁇ at the last stage of each channel. Perform by turning off.
  • the light amount control device 16C turns on / off the semiconductor laser for excitation of the fiber amplifier 174, that is, sets the intensity of the excitation light from the semiconductor laser 174 to one of a predetermined level and a zero level. It can also be done by setting it as an alternative, or the drive current of the semiconductor laser 174 By adjusting the current value, the intensity of the pumping light from the semiconductor laser 174 can be adjusted to the first level at which the fiber amplifier 171 n can be amplified, and the fiber amplifier 171.
  • the first level or the second level can be set either the first level or the second level at which amplification is disabled.
  • the non-amplification state the light absorption becomes large, and the output from the fiber amplifier becomes almost zero, so that the output of each optical path 172 n is turned off.
  • the semiconductor laser 174 is turned on and off, the power is not consumed in the state where the semiconductor laser 174 is turned off, so that energy can be saved.
  • the intensity of the pump light from the semiconductor laser 174 is switched between the first level and the second level, the first level and the second level may be fixed values. You don't have to. In other words, in a fiber amplifier, whether the state of amplification is possible or not is determined by going up or down from a certain value of the excitation light intensity.
  • the average light output (light quantity) of the entire bundle can be controlled at 1 / 128th of the maximum output light quantity (about 1% or less). is there. That is, the dynamic range can be set in a wide range from ⁇ to 1 128. Since each optical path 172 n is configured by using the same component, the optical output of each optical path 172 n is equal to the harm from the viewpoint of design.
  • the light quantity control has good linearity.
  • the wavelength converter 163 for wavelength-converting the output of the optical amplifier 161, that is, the output of the bundle-fiber 173 is provided. Is proportional to the number of fibers with the output of each optical path 172 n , that is, the output of the fiber amplifier 171 n turned on.Therefore, for the set light amount, a linear output of 1/128 of the maximum output light amount It is a harm that control is possible in principle.
  • each optical path 172 n the output variation of each optical fiber (optical path 172 n ) and the output variation due to the wavelength conversion efficiency variation for each optical fiber output are measured in advance.
  • This is a map of the intensity of the optical output from the wavelength converter 163 corresponding to the on / off status of the optical output from each optical fiber based on the result (a conversion table of the output intensity corresponding to the fiber group to be turned on).
  • a first output intensity map is created, and the first output intensity map is stored in the memory 51 attached to the main controller 50.
  • This first output intensity map may be stored in the memory 51 in the form of a table, or may be stored as a function or a coefficient. The same applies to the second and third output intensity maps described later.
  • the light amount control device when performing the light amount control by the first function, the light amount control is performed based on the set light amount given from the main control device 50 and the output intensity map.
  • the light quantity control device 16C controls the frequency control of the pulse light output from the EOM 160 in the second function by changing the frequency of the rectangular wave (voltage pulse) applied to the EOM 160C. Do. Since the frequency of the pulse light output from the EOM 160 C matches the frequency of the voltage pulse applied to the EOM 160 C, the frequency of the output pulse light is controlled by controlling the applied voltage. It is.
  • the frequency of the rectangular wave applied to the EOM 160 C is 100 kHz.
  • this frequency is set to 110 kHz
  • the number of optical pulses output from the EOM 160 C per unit time increases by 10%.
  • pulse light per unit time increases by 10% for each channel and one light pulse If the light energy per unit light is the same, that is, if the peak power of the pulsed light is constant, the output light intensity (light amount) of each optical path 172 n per unit time also increases by 10%.
  • the wavelength conversion unit 163 for performing wavelength conversion of the output light of each channel of the optical amplification unit 161 is provided.
  • the light intensity is proportional to the frequency of the output pulse of each channel if the peak power is constant.
  • the light quantity control by the second function is excellent in linearity.
  • the pulse light output from the EON / M 60 C is, via the delay unit 1 67, full multiplexing amplifier 1 68 ", since the input of the 1 7 1 n, in practice, re Niariti is as described above That is, in general, the gain of a fiber amplifier depends on the input light intensity, and therefore, when the frequency of the output light of the EOM 160 C is changed, the fiber amplifiers 168 n and 17 1 the input light intensity is changed in n, resulting fiber amplifier 1 68 n, 1 7 pulsed light peak power of output from the 1 n is because sometimes changes. fiber amplifier 1 68 n, 1 7 1 By properly designing coordinator, it is possible to suppress this peak power change, but it may reduce other performances such as the optical output efficiency of the fiber amplifier.
  • the input frequency intensity dependence of the fiber amplifier output is measured in advance, and based on the measured value, each channel of the optical amplifier 161 (corresponding to the frequency of the pulse light input to the optical amplifier 161) Create a second output intensity map (a conversion table of the output intensity of the optical amplifier 161, corresponding to the frequency of the output light of the EOM), which is a map of the output intensity of the EOM, and store the second output intensity map in the memory.
  • a second output intensity map a conversion table of the output intensity of the optical amplifier 161, corresponding to the frequency of the output light of the EOM
  • the light amount control device 16C performs the light amount control based on the set light amount given from the main control device 50 and the above-mentioned second output intensity map. It has become.
  • the light amount control device 16C controls the peak power of the pulse light output from the EOM 160 C in the third function by controlling the peak intensity of the voltage pulse applied to the EOM 160 C. Do.
  • the peak power of the output light of EOM 160 C depends on the peak intensity of the voltage pulse applied to EOM 160 C. It is.
  • the wavelength conversion section 163 for performing wavelength conversion of the output light of each channel of the optical amplification section 161 is provided, but the output light intensity of the wavelength conversion section 163 is
  • the peak intensity of the pulsed light output from each optical fiber (optical path 1 72 n ) exhibits a nonlinear dependence that is at most proportional to the power of the harmonic order.
  • the 193 nm light output intensity shows a change in intensity that is proportional to the eighth power at the maximum of the peak power of the fiber amplifier output.
  • the dependency of the peak power of the pulse light output from the EOM 160 C on the peak intensity of the voltage pulse applied to the EOM 160 C is c 0 s (V). Therefore, the nonlinear dependence of the wavelength conversion section 163 is moderated. Therefore, in the light source device having the wavelength conversion unit as in the present embodiment, it is not possible to control the intensity (light amount) of the output light by controlling the peak intensity of the voltage pulse applied to the EOM160C. It makes sense.
  • the amplification gain of the fiber amplifier depends on the input light intensity. Therefore, if the peak intensity of the pulse light output from the EOM 160 C is changed, the fiber amplifiers 168 n , 1 7 1 n input light intensity is changed, there Ru if the result fiber amplifier 1 6 8 n, 1 7 peak power of the outputted pulse light from 1 n is changed. Fiber amplifier 1 6 8 n, 1 7 1 n properly by the designing Li case, although it is possible to suppress the peak Kupawa change, reducing the other performance such as the light output efficiency of the fiber amplifier There is also.
  • the dependence of the output of the fiber amplifier on the input pulse peak intensity is measured in advance, and based on the measured value, the optical amplification unit 16 1 corresponding to the peak intensity of the pulse light input to the optical amplifier 16
  • a third output intensity map (a conversion table of the intensity of the output pulse light of the optical amplifier unit 161 corresponding to the peak intensity of the output light of the EOM), which is a map of the output intensity of each channel, is created.
  • the output intensity map is stored in the memory 51.
  • This third output intensity map is a purple It may be an external light intensity map.
  • the light amount control device 16C performs the light amount control based on the set light amount given from the main control device 50 and the third output intensity map. It is supposed to do.
  • an E 0 M for transmittance control is provided at the output stage of the DFB semiconductor laser 160 A, and the EOM is changed by changing the voltage applied to the E 0 M. It is also possible to change the emission energy from the optical amplification unit and wavelength conversion unit per unit time by changing the transmittance of the light.
  • the second and third functions of the light amount control device 16C can control the light amount of the output light of the light source device 16 more finely than the first function. is there.
  • the first function can set a wider dynamic range than the second and third functions.
  • the light amount control device 16C also controls the start and stop of the pulse output based on an instruction from the main control device 50.
  • the polarization adjustment device 1 6 D by than the optical fiber amplifier 1 7 l n for controlling the polarization characteristics of the front side of the optical component, to circularly polarized light of the light emitted from the optical fiber amplifier 1 7 1 n. If the doped fiber of the optical fiber amplifier 171 n has a substantially cylindrically symmetric structure and is relatively short, the light incident on the optical fiber amplifier 171 n is circularly polarized. Also, the light emitted from the optical fiber amplifier 17 1 n can be circularly polarized.
  • the front side of the optical component than the optical fiber amplifier 1 7 1 n may relay optical fiber or the like (not shown) for coupling the elements of the optical amplification section 1 6 1 described above optically.
  • Methods for controlling the polarization characteristics of such relay optical fibers include, for example, There is a method of adding anisotropic mechanical stress to the ray fiber, and this method is also employed in the present embodiment.
  • a relay optical fiber has a refractive index distribution that is cylindrically symmetric. However, when an anisotropic mechanical stress is applied, an anisotropic stress is generated in the relay optical fiber. An isotropic refractive index distribution occurs. By controlling the amount of such anisotropic refractive index distribution, the polarization characteristics of the relay optical fiber can be controlled.
  • the amount of change in the refractive index distribution due to the stress of the relay optical fiber and the polarization characteristics of other optical components generally depend on temperature.
  • the polarization adjusting device 16D performs temperature control to keep the ambient temperature of the relay optical fiber or the like constant so that the circular polarization once performed can be maintained.
  • the polarization state of light is monitored at any position downstream of the relay optical fiber, and based on the monitoring result, the polarization characteristics of the relay optical fiber, that is, the refractive index distribution. May be controlled.
  • the illumination optical system 12 includes a beam shaping optical system 18, a fly-eye lens system 22 as an optical integrator (homogenizer), an illumination system aperture stop plate 24, a beam splitter 26, and a first optical system. It has a relay lens 28A, a second relay lens 28B, a fixed reticle blind 30A, a movable reticle blind 30B, a mirror M for bending the optical path, and a condenser lens 32.
  • the beam shaping optical system 18 converts the cross-sectional shape of the LB (hereinafter referred to as “laser beam”) generated by the wavelength conversion of the wavelength conversion unit 16 3 of the light source device 16 into the laser beam. It is shaped so as to efficiently enter the fly-eye lens system 22 provided behind the LB optical path, and includes, for example, a cylinder lens and a beam expander (both not shown).
  • the fly-eye lens system 22 is arranged on the optical path of the laser beam LB emitted from the beam shaping optical system 18 and is used to illuminate the reticle R with a uniform illuminance distribution.
  • a surface light source consisting of a number of light source images, that is, a secondary light source.
  • the laser beam emitted from the secondary light source is also referred to as “exposure light IL” in this specification.
  • An illumination system aperture stop plate 24 made of a disc-shaped member is arranged near the exit surface of the fly-eye lens system 22.
  • This illumination system aperture stop plate 24 is provided at equal angular intervals, for example, an aperture stop composed of a normal circular aperture, an aperture stop for reducing the ⁇ value, which is a lithocoherence factor, compared to a small circular aperture, and an annular aperture.
  • a ring-shaped aperture stop, a modified aperture stop with multiple apertures eccentrically arranged for the modified light source method (only two of these apertures are shown in Fig. 1), etc. Has been done.
  • the illumination system aperture stop plate 24 is configured to be rotated by a drive unit 4 such as a motor controlled by a main controller 50 so that any one of the apertures can be selected according to the reticle pattern.
  • the aperture is selectively set on the optical path of the exposure light IL.
  • a beam splitter 26 having a small reflectance and a large transmittance is arranged on the optical path of the exposure light I coming out of the illumination system aperture stop plate 24, and a fixed reticle blind 3 is provided on the optical path behind this.
  • a relay optical system including a first relay lens 28A and a second relay lens 28B is provided with an OA and a movable reticle blind 30B interposed therebetween.
  • the fixed reticle blind 30A is disposed on a plane slightly defocused from a conjugate plane with respect to the pattern plane of the reticle R, and has a rectangular opening defining an illumination area 42R on the reticle R.
  • a movable reticle blind 30B having an opening whose position and width in the scanning direction is variable is arranged near the fixed reticle blind 30A, and the movable reticle blind 30B is provided at the start and end of scanning exposure. By further restricting the illumination area 42R via B, unnecessary portions of the exposure are prevented.
  • the exposure light IL passing through the second relay lens 28 B is directed toward the reticle R.
  • a bending mirror M that reflects light is disposed, and a condenser lens 32 is disposed on the optical path of the exposure light I behind the mirror M.
  • an integrator sensor 46 and a reflected light monitor 47 are arranged on one of the optical paths that are bent vertically by the beam splitter 26 in the illumination optical system 12 and on the other optical path.
  • the integrator sensor 46 and the reflected light monitor 47 have high sensitivity in the deep ultraviolet region and the vacuum ultraviolet region and have a high response frequency for detecting the pulse light emission of the light source device 16.
  • a type diode is used.
  • a semiconductor light-receiving element having a GaN-based crystal can also be used as the integrator sensor 46 and the reflected light monitor 47.
  • the entrance surface of the fly-eye lens system 22, the arrangement surface of the movable reticle blind 30 B, and the pattern surface of the reticle R are optically set to be conjugate with each other, and the emission of the fly-eye lens system 22 is performed.
  • the light source surface formed on the surface side and the Fourier transform plane (exit pupil plane) of the projection optical system PL are optically set to be conjugate to each other, and form a Koehler-single illumination system.
  • a laser beam LB pulsed from the light source device 16 is incident on the beam shaping optical system 18, where the laser beam LB at the rear is formed. After its cross-sectional shape is shaped so as to efficiently enter the eye lens system 22, the light enters the fly-eye lens system 22. As a result, a secondary light source is formed on the exit-side focal plane of the fly-eye lens system 22 (the pupil plane of the illumination optical system 12).
  • the exposure light IL emitted from the secondary light source passes through one of the aperture stops on the illumination system aperture stop plate 24 and then reaches a beam splitter 26 having a large transmittance and a small reflectance.
  • Exposure light IL transmitted through the beam splitter 26 passes through the first relay lens 28 A, passes through the rectangular opening of the fixed reticle blind 30 A and the movable reticle blind 30 B, and then passes through the second relay lens. After passing through 28B, the optical path is bent vertically downward by the mirror M, and then passes through the condenser lens 32, on the reticle R held on the reticle stage RST.
  • the rectangular illumination area 42R is illuminated with a uniform illuminance distribution.
  • the exposure light IL reflected by the beam splitter 26 is received by the integrator sensor 46 via the condenser lens 44, and the photoelectric conversion signal of the integrator sensor 46 is converted to a peak hold circuit (not shown) and an AZD. It is supplied to the main controller 50 as an output DS (digital / pulse) via a converter.
  • the correlation coefficient between the output DS of the integrator sensor 46 and the illuminance (exposure amount) of the exposure light I on the surface of the wafer W is obtained in advance, and the storage device provided in the main controller 50 is provided. As stored in memory 51.
  • the illuminated area 42 R on the reticle R illuminates and the reflected light flux reflected on the pattern surface of the reticle (the lower surface in Fig. 1) passes through the condenser lens 32 and the relay optical system in the opposite direction to the front.
  • the light is reflected by the beam splitter 26 and received by the reflected light monitor 47 via the condenser lens 48.
  • the Z tilt stage 58 is below the projection optical system PL, the exposure light IL transmitted through the pattern surface of the reticle is applied to the projection optical system PL and the surface of the wafer W (or a reference mark plate described later).
  • the reflected light flux passes through the projection optical system P, passes through the reticle R, the condenser lens 32, and the relay optical system in the reverse direction, and is reflected by the beam splitter 26.
  • the reflected light is received by the reflected light monitor 47 via the optical lens 48.
  • each optical element disposed between the beam splitter 26 and the wafer W has an anti-reflection film formed on its surface, the exposure light IL is slightly reflected on its surface, and these reflected lights are also reflected.
  • the light is received by the optical monitor 47.
  • the photoelectric conversion signal of the reflected light monitor 47 is supplied to the main controller 50 via a peak hold circuit (not shown) and an AZD converter.
  • the reflected light monitor 47 is mainly used for measuring the reflectance of the wafer W. Note that the reflected light monitor 47 may be used for the preliminary measurement of the transmittance of the reticle R.
  • a diffractive optical element may be used together with the fly-eye lens system 22.
  • the light source device 16 and the illumination optical system 12 may be connected via a diffractive optical element. That is, a diffractive optical element in which a diffractive element is formed corresponding to each fiber of a bundle fiber is provided in the beam shaping optical system 18, and a laser beam output from each fiber is diffracted to form a fly-eye lens system 2. It may be superimposed on the incident surface of No. 2. In the present embodiment, the output end of the bundle-one fiber may be arranged on the pupil plane of the illumination optical system.
  • the first function causes the intensity distribution on the pupil plane (ie, the secondary The shape and size of the light source), which may differ from the optimal shape and size for the reticle pattern. Therefore, it is desirable to superimpose the laser beam from each fiber on the pupil plane of the illumination optical system or the entrance plane of the optical integrator using the above-described diffractive optical element.
  • the reticle R Even if the distribution of the light output portion of the bundle-one fiber 1 73 changes due to the first function of the light amount control device 16 C described above, the reticle R The uniformity of the illuminance distribution can be sufficiently ensured on both the pattern surface (object surface) and the surface (image surface) of the wafer W.
  • a reticle R is mounted on the reticle stage RST, and is held by suction via a vacuum chuck (not shown).
  • the reticle stage RST can be finely driven in a horizontal plane (XY plane), and is moved in the scanning direction (here, the Y direction, which is the horizontal direction in FIG. 1) by a reticle stage driving unit 49. Scanning is performed within a fixed stroke range.
  • the position and the rotation amount of the reticle stage RST during this scanning are measured by an external laser interferometer 54 R via a movable mirror 52 R fixed on the reticle stage RST, and the laser interferometer 54
  • the measured value of R is supplied to the main controller 50.
  • the material used for the reticle R needs to be properly used depending on the wavelength of the exposure light IL. That is, when using exposure light with a wavelength of 193 nm, synthetic quartz can be used, but when using exposure light with a wavelength of 157 nm, synthetic quartz doped with fluorite or fluorine is used. , Or must be formed of quartz or the like.
  • the projection optical system P L is, for example, a telecentric reduction system on both sides, and is composed of a plurality of lens elements 70 a, 70 b,... Having a common optical axis in the Z-axis direction. Further, as the projection optical system PL, one having a projection magnification) 8 of, for example, 1Z4, 15 or 16 is used.
  • the illumination area 42 R on the reticle R is illuminated by the exposure light I
  • the pattern formed on the reticle R is projected by the projection optical system PL at a projection magnification ⁇ .
  • the reduced image is projected and transferred to a slit-shaped exposure area 42 W on a wafer W having a resist (photosensitive agent) applied on the surface.
  • a plurality of lens elements are independently movable.
  • the uppermost lens element 70a closest to the reticle stage RS is held by a ring-shaped support member 72.
  • This support member 72 is a telescopic drive element, for example, a piezo element 74a. , 74 b, 74 c (the drive element 74 c on the back side of the drawing is not shown), and is supported at three points and connected to the lens barrel 76.
  • the driving elements 74a, 74b, and 74c allow the three points around the lens element 70a to be independently moved in the optical axis AX direction of the projection optical system PL. I have.
  • the lens element 70a can be translated along the optical axis AX according to the displacement of the driving elements 74a, 74b, and 74c, and can be moved perpendicularly to the optical axis AX. It can also be arbitrarily inclined with respect to a simple plane.
  • the voltages applied to these drive elements 74 a, 74 b, and 74 c are controlled by the imaging characteristic correction controller 78 based on a command from the main controller 50, whereby The displacement amounts of the drive elements 74a, 74b, and 74c are controlled.
  • the optical axis AX of the projection optical system PL refers to the optical axis of the lens element 70 b fixed to the lens barrel 76 and other lens elements (not shown).
  • the relationship between the vertical amount of the lens element 70a and the change amount of the magnification (or distortion) is obtained in advance by an experiment, and this is stored in, for example, the memory 51, and the correction is mainly performed.
  • the controller 50 calculates the vertical amount of the lens element 70a from the magnification (or device! ⁇ 1) corrected by the controller 50, and gives instructions to the imaging characteristic correction controller 78 to drive the drive elements 74a, 7a. By driving 4b and 74c, magnification (or day! ⁇ 1) correction is performed. That is, in the present embodiment, the imaging characteristic of the projection optical system PL is corrected by the imaging characteristic correction controller 78, the driving elements 74a, 74b, 74c, and the main controller 50. An imaging characteristic correction device is configured.
  • the relationship between the vertical amount of the lens element 70a and the amount of change in magnification or the like may use an optically calculated value. In this case, the vertical amount of the lens element 70a and the amount of change in magnification may be used. The experiment process for finding the relationship can be omitted.
  • the lens element 70a closest to the reticle R is movable.However, this element 70a has a greater effect on magnification and distance! If one of the controls is selected and the same condition is satisfied, any lens element may be configured to be movable for adjusting the lens interval instead of the lens element 70a. good.
  • At least one lens element other than the lens element 70a is moved to obtain other optical characteristics such as curvature of field, astigmatism, coma, or spherical aberration. And so on.
  • a sealing chamber is provided between specific lens elements near the center of the projection optical system PL in the optical axis direction, and the pressure of gas in the sealing chamber is adjusted by a pressure adjusting mechanism such as a bellows pump.
  • An imaging characteristic correction mechanism that adjusts the magnification of the projection optical system PL may be provided, or, for example, an aspherical lens is used as a part of the lens elements constituting the projection optical system PL, and this is rotated. You may do it. In this case, so-called rhombic distortion can be corrected.
  • a parallel plane plate may be provided in the projection optical system PL, and the imaging characteristic correction mechanism may be configured by a mechanism that tilts or rotates the parallel flat plate.
  • an atmospheric pressure sensor 77 that measures the atmospheric pressure in the chamber 11 is provided.
  • the measured value of the atmospheric pressure sensor 77 is supplied to the main controller 50, and the main controller 50 uses the standard atmospheric pressure sensor 77 based on the measured value of the atmospheric pressure sensor 77.
  • an instruction is given to the imaging characteristic correction controller 78 in consideration of the variation in the atmospheric pressure to correct the imaging characteristic of the projection optical system PL.
  • the above-mentioned change of the oscillation wavelength is performed by the laser controller 16B, based on an instruction from the main controller 50, by actively controlling the temperature of the etalon element constituting the beam monitor mechanism 164, and The set wavelength (target wavelength) at which the resonance wavelength (detection reference wavelength) at which the transmittance of the element is maximized is changed, and the oscillation wavelength of the DFB semiconductor laser 16 OA matches the changed set wavelength.
  • the DFB semiconductor This is easily achieved by feedback controlling the temperature of the laser 160A.
  • the method of calculating the atmospheric pressure fluctuation, the irradiation fluctuation, and the like of the imaging characteristics by the main controller 50 is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 9-213139, Since it is publicly known, detailed description is omitted here.
  • the XY stage 14 is driven two-dimensionally by a wafer stage drive unit 56 in the Y direction, which is the scanning direction, and the X direction, which is orthogonal to the scanning direction (the direction orthogonal to the plane of FIG. 1).
  • a wafer W is held on a Z tilt stage 58 mounted on the XY stage 14 by vacuum suction or the like via a wafer holder (not shown).
  • the Z-tilt stage 58 adjusts the position of the wafer W in the Z direction (the position of the wafer) by, for example, three actuators (piezo elements or voice coil motors), and moves the XY plane (projection optical system PL).
  • the position of the XY stage 14 is measured by an external laser interferometer 54 W through a movable mirror 52 W fixed on the Z tilt stage 58, and the measurement of the laser interferometer 54 W is performed.
  • the value is supplied to the main controller 50.
  • the moving mirror actually has an X moving mirror having a reflecting surface perpendicular to the X axis and a Y moving mirror having a reflecting surface perpendicular to the ⁇ axis.
  • X-axis position measurement, Y-axis position measurement, and rotation (including jogging, pitching, and rolling) measurements are provided, respectively. In Figure 1, these are typically used as moving mirrors.
  • a light receiving surface having the same height as the exposure surface of the wafer W is provided near the wafer W, and the light amount of the exposure light IL passing through the projection optical system PL is detected.
  • Dose monitor 59 is provided.
  • the irradiation amount monitor 59 has a rectangular housing in a plan view extending in the X direction around the exposure area 42 W, which is larger than the exposure area 42 W. Is formed. This opening actually forms the ceiling surface of the housing It is formed by removing a part of the light shielding film formed on the upper surface of the light receiving glass made of quartz or the like. An optical sensor having a light receiving element such as a Si-type PIN-type photodiode is disposed directly below the opening via a lens.
  • the irradiation amount monitor 59 is used for measuring the intensity of the exposure light I irradiated to the exposure area 42 W.
  • a light amount signal corresponding to the amount of light received by the light receiving element constituting the irradiation amount monitor 59 is supplied to the main controller 50.
  • the optical sensor does not necessarily need to be provided inside the Z tilt stage 58, and an optical sensor is provided outside the Z tilt stage 58, and the illumination light beam relayed by the relay optical system is used for optical fiber or the like. Needless to say, the light sensor may be guided to the optical sensor via the optical sensor.
  • a reference mark plate FM used for performing a reticle alignment or the like described later is provided on the Z tilt stage 58.
  • the surface of the reference mark plate FM is substantially the same height as the surface of the wafer W.
  • Reference marks such as a reticle alignment reference mark and a baseline measurement reference mark are formed on the surface of the reference mark plate FM.
  • the exposure apparatus 10 actually has a reticle alignment system for performing reticle alignment.
  • the main controller 50 drives the reticle stage RST and the XY stage 14 via the reticle stage drive unit 49 and the wafer stage drive unit 56, thereby forming a rectangular shape.
  • a reticle alignment reference mark on the reference mark plate FM is set in the exposure area 4 2 W, and the reticle R and Z tilt tilt so that the reticle mark image on the reticle R almost overlaps the reference mark
  • the position relative to the stage 58 is set.
  • both marks are imaged by the main controller 50 using a reticle alignment system, and the main controller 50 processes the image signals and projects the reticle marks onto the corresponding reference marks. image Calculate the amount of displacement in the X and Y directions.
  • focus offset / leveling offset focal position of the projection optical system PL
  • Image plane tilt etc.
  • the main controller 50 controls the baseline amount of the wafer-side office-side alignment sensor (not shown) provided on the side surface of the projection optical system PL. Measurement is also performed.
  • a reference mark for baseline measurement is formed on the reference mark plate F in a predetermined positional relationship with respect to the reference mark for reticle alignment, and the reticle mark is provided via the reticle alignment system.
  • the amount of misalignment of the alignment sensor is measured via the alignment sensor on the wafer side.
  • the line amount that is, the relative positional relationship between the reticle projection position and the alignment sensor is measured.
  • the exposure apparatus 10 of the present embodiment has a light source whose on / off is controlled by the main controller 50, and a large number of light sources are directed toward the image forming plane of the projection optical system PL.
  • An obliquely incident light type multi-point focal position detection system (focus sensor) composed of a light receiving optical system 60b for receiving light is provided.
  • the main controller 50 controls the inclination of the reflected light flux of the parallel flat plate (not shown) in the light receiving optical system 60b with respect to the optical axis, so that the focus detection system (6 Calibration is performed by giving offsets to 0 a and 60 b).
  • the image plane of the projection optical system PL and the surface of the wafer W coincide with each other within the range (width) of the depth of focus within the above-described exposure area 42 W.
  • This implementation The detailed configuration of the multi-point focal position detection system (focus sensor) similar to the embodiment is described in, for example, Japanese Patent Application Laid-Open No. Hei 6-284403 and US Patent Nos. 5,448,333 corresponding thereto. No. 2, etc. To the extent permitted by the national laws of the designated or designated elected country in this international application, the disclosures in the above publications and U.S. patents are incorporated herein by reference.
  • the main controller 50 sets the Z tilt stage so that the defocus becomes zero based on the defocus signal (defocus signal) from the light receiving optical system 60b, for example, the S-carp signal.
  • the autofocus (automatic focusing) and the autoleveling are executed by controlling the Z position 8 through a drive system (not shown).
  • the reason why a parallel flat plate is provided in the light receiving optical system 60b to give an offset to the focus detection system (60a, 60b) is that, for example, the lens element 70a is used for magnification correction.
  • the projection optical system PL absorbs the exposure light IL, the re-imaging characteristics change and the position of the imaging surface fluctuates.
  • the relationship between the vertical amount of the lens element 70a and the focus change amount is obtained in advance by experiments, and is stored in the memory 51, for example.
  • the relationship between the vertical amount of the lens element 70a and the focus change amount may use a calculated value.
  • the self-leveling may not be performed in the scanning direction, but may be performed only in the non-scanning direction orthogonal to the scanning direction.
  • the main controller 50 includes a so-called microcomputer (or workstation) including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. In addition to performing the various controls described above, it controls, for example, synchronous scanning of the reticle R and the wafer W, stepping of the wafer W, exposure timing, and the like so that the exposure operation is properly performed. Further, in the present embodiment, the main control device 50 controls the scanning exposure as described later. It controls the amount of exposure in the case of light, calculates the amount of change in the imaging characteristics of the projection optical system PL by calculation, and, based on the calculation result, passes the projection optical system PL through the imaging characteristic correction controller 78.
  • a microcomputer or workstation
  • CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • Shot map data is prepared in advance based on the shot arrangement, shot size, exposure order of each shot, and other necessary data input from the input / output device 62 (see Fig. 1) by the operator. (Data defining the exposure order and scanning direction of each shot area) are created and stored in the memory 51 (see FIG. 1).
  • the output of the integrator sensor 46 is pre-calibrated against the output of a reference illuminometer (not shown) installed on the tilt stage 58 at the same height as the image plane (ie, the surface of the wafer). (Calibration). Calibration of the Integra sensor 46 means that the output of the Integra sensor 46 is Obtaining a conversion coefficient (or conversion function) for converting to light quantity. When this conversion coefficient is used, the amount of exposure (energy) given to the image plane can be indirectly measured from the output of the integrator sensor 46.
  • the energy monitor in the beam monitor mechanism 164 and the photoelectric conversion elements 1.80, 18 in the optical amplifier 161 1 and the outputs of the photoelectric conversion elements 18 2 in the wavelength converter 16 3 are also calibrated, and the correlation coefficient of each sensor output with respect to the output of the integrator sensor 46 is also obtained in advance. Is stored.
  • the output of the reflected light monitor 47 is calibrated against the output of the integrator sensor 46 after the above calibration is completed, and the output of the integrator sensor 46 and the output of the reflected light monitor 47 are compared. It is assumed that the number of relations is obtained in advance and stored in the memory 51.
  • the lighting conditions number of the projection optical system, the shape of the secondary light source (type of aperture stop 24), the coherence Exposure conditions, including factors and reticle pattern types (contact holes, line and space, etc.), reticle types (phase difference reticle, half I-one reticle, etc.) and minimum line width or exposure tolerance, etc.
  • the main controller 50 sets the aperture stop (not shown) of the projection optical system PL, selects and sets the aperture of the illumination system aperture stop plate 24, and responds to the registry sensitivity.
  • Set the target integrated exposure amount (the amount corresponding to the set light amount).
  • the main controller 50 turns on and off the output of the bundle-one fiber 173 to make the output light amount from the light source device 16 for obtaining the target integrated exposure amount substantially coincide with the set light amount. Is selected, and this selection command is given to the light quantity control device 16C.
  • the light quantity control device 16 C causes the fiber amplifiers 17 1 1 n of each channel to respond to the selection command by the first function described above. Is turned on and off, and the exposure Will be roughly adjusted.
  • main controller 50 loads reticle R to be exposed onto reticle stage R ST using a reticle loader (not shown).
  • reticle alignment is performed using the reticle alignment system, and baseline measurement is performed.
  • main controller 50 instructs a wafer transfer system (not shown) to replace wafer W.
  • the wafer is exchanged (if there is no wafer on the stage, a simple wafer load) is performed by a wafer transfer system and a wafer transfer mechanism (not shown) on the XY stage 14.
  • the so-called search element and finer disclosed in Japanese Patent Application No. 061 and Japanese Patent Application Laid-Open No. Hei 9-136202 and U.S. Pat. (For example, statistics using the least squares method disclosed in Japanese Patent Application Laid-Open No. 61-44492 and corresponding US Pat. Nos. 4,780,617).
  • the reticle pattern is repeatedly transferred to a plurality of shot areas on the wafer W by a step-and-scan method.
  • the main controller 50 applies the target integrated exposure amount determined according to the exposure conditions and the resist sensitivity to the wafer W, so that the output of the integrator sensor 46 is monitored while the light amount controller 50 is monitored. Give a command to 16 C.
  • the coarse adjustment of the exposure amount is performed by the first function described above, and the laser beam (light beam) from the light source device 16 is controlled by the second and third functions described above. It controls the frequency and peak power of ultraviolet pulse light, and performs fine adjustment of the exposure.
  • the main controller 50 controls the illumination system aperture stop plate 24 via the driving device 40, and further controls the opening / closing operation of the movable reticle blind 30B in synchronization with the operation information of the stage system. .
  • main controller 50 instructs a wafer transfer system (not shown) to replace wafer W.
  • the wafer is exchanged by the wafer transfer system and the wafer transfer mechanism (not shown) on the XY stage 14, and thereafter, the search alignment and the fine alignment are performed on the replaced wafer in the same manner as described above.
  • the main controller 50 causes the irradiation fluctuation of the imaging characteristics (including the focus fluctuation) of the projection optical system PL from the start of the exposure of the first wafer W to the integrator sensor 46 and the reflected light monitor.
  • a command value which is obtained based on the measurement value of 47 and corrects this irradiation variation, is given to the imaging characteristic correction controller 78 and an offset is given to the light receiving optical system 60b.
  • the main controller 50 also obtains the atmospheric pressure fluctuation of the imaging characteristics of the projection optical system PL based on the measurement value of the atmospheric pressure sensor 77, and issues a command value for correcting this irradiation fluctuation.
  • the offset is given to the imaging characteristic correction controller 78 and the light receiving optical system 60b.
  • the reticle pattern is transferred to a plurality of shot areas on the wafer W by a step-and-scan method.
  • the wafer exchange and the step-and-scan exposure are sequentially repeated in the same manner as described above.
  • the main controller 50 controls the laser controller 16 B based on the monitoring result of the beam monitor mechanism 16 4.
  • Feedback control is performed to maintain the oscillation wavelength of the laser light source 16 OA stably at the set wavelength via the. For this reason, generation of aberration (imaging characteristics) of the projection optical system PL due to wavelength fluctuation or its fluctuation is prevented, and the image characteristics (optical characteristics such as image quality) do not change during pattern transfer.
  • the main controller 50 gives instructions to the imaging characteristic correction controller 44 to drive the drive elements 74a, 74b, and 74c, and the above-described atmospheric pressure fluctuation component of the projection optical system PL.
  • the atmospheric pressure, temperature, and scale from the standard state are determined based on the measurement values of the environmental sensors 77. Degrees of change, etc. are calculated, and the amount of wavelength change for almost canceling the environmental change of the imaging characteristics of the projection optical system PL due to the change of the atmospheric pressure, temperature, humidity, etc. is calculated, and the amount of change in wavelength is calculated.
  • the oscillation wavelength of the laser light source 16 OA may be positively changed accordingly.
  • the environment sensor 77 may be a sensor that detects atmospheric pressure.
  • Such a change of the oscillation wavelength is performed based on an instruction from the main controller 50, in which the laser controller 16B actively controls the temperature of the etalon element constituting the beam monitor mechanism 164 to transmit the etalon element.
  • Change the set wavelength (target wavelength) at which the resonance wavelength (detection reference wavelength) at which the efficiency becomes the maximum is adjusted, and make sure that the oscillation wavelength of the DFB semiconductor laser 160 A matches the changed set wavelength. This is easily achieved by feedback controlling the temperature of the DFB semiconductor laser 16 OA.
  • fluctuations in the imaging characteristics such as aberrations, projection magnifications, and focal positions of the projection optical system PL caused by changes in atmospheric pressure, temperature, humidity, and the like are simultaneously canceled. can do.
  • Such a wavelength change more specifically, a change in the set wavelength, and the change after this change
  • the control of stabilizing the oscillation wavelength of the laser light source 16 OA based on the set wavelength is performed in the following cases.
  • the standard atmospheric pressure is usually set to the average atmospheric pressure of the delivery destination (eg, factory) where the exposure apparatus is installed. Therefore, when there is an elevation difference between the assembly site where the exposure apparatus is manufactured and the destination where the exposure apparatus is installed (relocation place), for example, the projection optical system and the like are operated under standard atmospheric pressure (such as average atmospheric pressure).
  • the exposure wavelength was shifted by the wavelength corresponding to the elevation difference at the assembly site, and then the projection optical system was adjusted.At the relocation site, the wavelength was returned to the exposure wavelength, or assembly was performed. On the ground, the adjustment of the projection optical system is performed under the exposure wavelength, and the exposure wavelength is shifted at the relocation site so as to offset the elevation difference.
  • the present embodiment for example, changing the wavelength of the illumination light by the projection optical system and changing the installation environment (pressure, temperature, humidity, etc. of the surrounding gas) of the projection optical system are not possible.
  • the fact that they are substantially equivalent is used.
  • the type of the glass material of the refraction element of the projection optical system is single, the equivalence is completely established, and even when there are a plurality of types of glass materials, the equivalence is almost satisfied. Therefore, by changing only the wavelength of the illumination light using the change characteristic of the refractive index of the projection optical system (particularly the refractive element) with respect to the installation environment, it is substantially equivalent to the case where the installation environment of the projection optical system changes. Can be realized.
  • the standard atmospheric pressure may be set arbitrarily, but for example, the optical performance of the projection optical system is the best. It is desirable that the atmospheric pressure be a reference when the adjustment is made so that the variation in the optical performance of the projection optical system or the like becomes zero at the standard atmospheric pressure.
  • the atmospheric pressure is the pressure of the atmosphere (gas) around the projection optical system PL. That is, in this specification, the atmospheric pressure has a normal meaning, that is, wider than the pressure of the atmosphere (air) and includes the pressure of the atmospheric gas.
  • the main controller 50 sets the degree of change of the set wavelength.
  • the driving elements 74a, 74b, and 74c are driven via the imaging characteristic correction controller 78 to exclude environmental fluctuations in the projection optical system PL that are corrected by changing the set wavelength. Correct the imaging characteristic fluctuation.
  • most of the environmental fluctuations in the imaging characteristics of the projection optical system PL are re-corrected by changing the set wavelength, and the remaining environmental fluctuations and irradiation fluctuations of the projection optical system PL are formed.
  • the correction is performed by driving the drive elements 74 a, 74 b, and 74 c by the image characteristic correction controller 78. As a result, high-precision exposure is performed with the imaging characteristics of the projection optical system PL almost completely corrected.
  • the main controller 50 may correct the imaging characteristic fluctuation in consideration of the environmental fluctuation during the change of the set wavelength.
  • the change of the set wavelength is performed at the above-mentioned predetermined timing, but if the change interval of the set wavelength is long, fluctuations in the atmospheric pressure, temperature, humidity, etc. occur during that time. Variations in the imaging characteristics of the optical system can be corrected.
  • the predetermined timing may be timing each time exposure of a predetermined number of wafers W is completed, or timing each time exposure of one shot on the wafer W is completed.
  • the predetermined number may be one, or may be a number corresponding to one lot.
  • the predetermined timing is a timing every time the exposure condition is changed.
  • the change of the exposure condition includes not only the change of the illumination condition but also all the cases where the condition regarding the exposure in a broad sense such as a change of a reticle is changed. For example, if the wavelength is changed in parallel with the change of the reticle and the change of the aperture stop of the illumination system during the so-called double exposure, there is almost no time loss, so that a decrease in throughput can be prevented.
  • the predetermined timing may be a timing at which a change in a physical quantity such as atmospheric pressure obtained based on the measurement value of the environment sensor 77 changes by a predetermined amount or more, or calculates the optical performance of the projection optical system PL. It may be performed almost in real time according to the interval (for example, number; s). Alternatively, the predetermined timing may be a timing at a predetermined time interval.
  • an irradiation variation model may be obtained by experiment or simulation for each of a plurality of representative wavelengths.
  • the changed wavelength is between the wavelengths for which the irradiation variation model is obtained, it is desirable to calculate the imaging characteristic or the amount of variation thereof by, for example, interpolation calculation.
  • the sensitivity characteristic of the resist (photosensitive agent) applied on the wafer W may change due to the wavelength shift.
  • the main controller 50 performs the integration described later according to the change in the sensitivity characteristic. It is desirable to control the exposure amount by changing at least one of the exposure parameters, that is, the scanning speed, the width of the illumination area, the intensity of the illumination light, and the oscillation frequency. It is preferable to determine the sensitivity characteristics of the resist by experiments or simulations corresponding to a plurality of representative wavelengths, and when the changed wavelength is between the wavelengths for which the sensitivity characteristics were determined, For example, it is desirable to calculate the sensitivity characteristic by interpolation calculation or the like.
  • the above-described coarse adjustment of the exposure amount may be performed by performing test emission before actual exposure, and performing control with an accuracy of 1% or less with respect to the exposure amount set value.
  • the dynamic range of the coarse adjustment of the exposure amount according to the present embodiment is in the range of 1 to 1/128. Although it can be set within the range, the required dynamic range is typically about 1 to 1 Z7, so the number of channels (the number of optical fibers) for which the optical output should be turned on is 128 to 8 What is necessary is to perform by controlling between.
  • the coarse adjustment of the exposure amount according to the difference in the resist sensitivity or the like for each wafer can be accurately performed by controlling the exposure amount by individually turning on / off the light output of each channel. .
  • an energy coarse adjuster such as an ND filter used in a conventional excimer laser exposure apparatus is not required.
  • the light amount control by the second and third functions by the above-described light amount control device 16C has characteristics that the control speed is fast and the control accuracy is high. It is possible to surely satisfy the required control requirements.
  • the dynamic range is a requirement for exposure control to correct the process variation in the shot area (for each chip) caused by, for example, the variation in the thickness of the resist in the same wafer.
  • Control accuracy is approximately ⁇ 1% of the set exposure amount
  • line width of one shot area is uniform Is a requirement for exposure control to realize the characteristic
  • the control accuracy is typically set to ⁇ 0.2% of the set exposure within the time of 2 O msec which is the exposure time of one shot, Control speed is about 1 ms.
  • the light amount control device 16C only needs to perform at least one of the light amount control by the second and third functions.
  • the scanning speed (scan speed) of the wafer W is set to V w , and the slit-shaped exposure on the wafer W is performed.
  • Region 4 If the width in the scanning direction (slit width) of 2 W is D and the repetition frequency of the pulse of the laser light source is “, the interval at which the wafer W moves between pulse emission is V W ZF.
  • Exposure light IL to be irradiated per spot The number of pulses (the number of exposure pulses) N is expressed by the following equation (3).
  • the exposure amount (integrated exposure amount) can be controlled by controlling any of the slit width D, the scanning speed Vw , the pulse repetition frequency F of the laser light source, and the pulse energy P. It is. There is a difficulty in adjusting the slit width D during scanning exposure due to the problem of response speed, so control either the scanning speed V w , the pulse repetition frequency F of the laser light source, or the pulse energy P Just do it.
  • the exposure light quantity may be controlled by combining any one of the light quantity control by the second and third functions of the light quantity control apparatus 16C and the scan speed.
  • the exposure light quantity control apparatus 16C may be controlled by combining any one of the light quantity control by the second and third functions of the light quantity control apparatus 16C and the scan speed.
  • the exposure condition of the wafer W is changed according to the reticle pattern to be transferred onto the wafer W.
  • the intensity distribution of the illumination light on the pupil plane of the illumination optical system ie, the shape and size of the secondary light source
  • the change in the exposure condition changes the illuminance on the wafer W, which also occurs due to the change in the reticle pattern. This is due to the difference in the area occupied by the light-shielding part (or transmission part) of the pattern.
  • the illuminance changes due to a change in at least one of the exposure condition and the reticle pattern at least one of the above-described frequency and peak power is controlled so that an appropriate exposure amount is given to the wafer (register). It is desirable to do. At this time, in addition to at least one of the frequency and the peak power, the scanning speed of the reticle and the wafer may be adjusted.
  • all of the second control device, the second control device, and the third control device are realized by the main control device 50. Of course, these control devices may be constituted by separate control devices.
  • the light amount control device 16C of the present embodiment described above has a light amount control function (first function) by individually turning on and off the light output from the light path, and the light output from the EOM 16C. It has a light quantity control function (second function) by frequency control of pulsed light and a light quantity control function (third function) by peak power control of pulse light output from EOM160C. since, the first function, by at least one of the second function and a third function, in addition to the stepwise light amount control by the individual on-off of the light output of the optical path 1 7 2 n, between each stage Fine adjustment of the light intensity of light is possible by controlling at least one of the frequency and peak power of the pulsed light output from the EOM 1600C. Output light, no matter what value the set light intensity is set to. The amount can be made to match the set amount of light.
  • the second function and the third function allow the peak power to be further controlled in addition to the frequency control of the pulse light output from the EOM 160C. Even if the peak power of the pulse light fluctuates, accurate light quantity control can be performed.
  • the present invention is not limited to this, and the light amount control device constituting the light source device according to the present invention may have at least one of the first to third functions.
  • the main controller 50 performs the above-described absolute wavelength calibration and subsequent set wavelength calibration prior to exposure, and sets the set wavelength during the exposure.
  • the calibration is completed via the laser controller 16B based on the monitoring result of the beam monitor mechanism. Feedback control of the temperature and current of the light source 16 OA.
  • the main controller 50 performs wavelength stabilization control for surely maintaining the center wavelength of the laser beam at the predetermined set wavelength based on the monitoring result of the beam monitor mechanism 164 after the set wavelength calibration is completed. While irradiating the reticle R with a laser beam and transferring the pattern of the reticle R to the wafer W via the projection optical system PL, high-precision exposure that is less affected by temperature fluctuations in the atmosphere is possible. become.
  • the main controller 50 sets the environment (standard state) from the standard state based on the measurement value of the environment sensor 77 at each of the above-mentioned predetermined timings after the exposure of the wafer W is started. Calculation of a wavelength change amount for almost canceling out a change in the imaging characteristics of the projection optical system PL due to a change in the atmospheric pressure, temperature, humidity, and the like, and changing the set wavelength according to the wavelength change amount. . As a result, various aberrations of the projection optical system PL are corrected at the same time, and the main controller 50 sets the center wavelength of the laser beam to a predetermined value by using the beam monitor mechanism 164 based on the set wavelength after the change.
  • the reticle R is irradiated with a laser beam and exposed, that is, the reticle pattern is transferred onto the wafer W via the projection optical system PL while performing wavelength stabilization control so as to reliably maintain the wavelength.
  • exposure can be performed with high accuracy in a state where there is no change in the environment (ie, a state in which the change in optical performance has been offset).
  • the main controller 50 changes the drive elements 74 a, 74 b, and 7 via the imaging characteristic correction controller 78 every time the set wavelength is changed.
  • 4 Drive c to correct the imaging characteristic fluctuation except for the environmental fluctuation of the projection optical system PL that is corrected by changing the set wavelength.
  • the correction is made by driving the driving elements 74a, 74b, and 74c by the imaging characteristic correction controller 78. As a result, a highly accurate exposure can be achieved with the imaging characteristics of the projection optical system PL almost completely corrected Light is done.
  • the laser light is monitored by the beam monitor mechanism 164 immediately after the laser light source 160 A in order to control the oscillation wavelength of the laser light source 16 OA.
  • the present invention is not limited to this.
  • a light beam is branched in the wavelength conversion section 163 (or behind the wavelength conversion section 163) and is split into a beam monitor mechanism 16
  • the beam may be monitored by the same beam monitor mechanism 18 as in 4.
  • the main controller 50 controls the laser controller 16B May be feedback controlled.
  • the oscillation wavelength control of the laser light source 16OA may be performed using the monitoring results of both beam monitoring mechanisms.
  • the detection reference wavelength of the etalon element constituting the beam monitor mechanism 183 is changed. The wavelength may be changed to the set wavelength.
  • the resonator length of the Fabry-Perot etalon constituting the wavelength detector is made variable by a piezo element or the like, and the resonator length of the resonance wavelength is changed. Dependencies may be used. This makes it possible to change the wavelength at high speed.
  • each optical path each channel
  • a mechanical or electrical shutter that blocks light incident on each optical path
  • a mechanical or electrical shirt that blocks light emission from each optical path
  • the optical amplifying section 161 has an optical path of 128 channels has been described.
  • the optical amplifying section may have one channel, Even in this case, the control of the light amount and the exposure amount by the frequency control and the peak power control of the pulse light output from the optical modulator such as the EOM described above can be suitably applied.
  • the polarization adjustment device 1 6 D is adjusted light emitted optical fiber amplifier 1 7 1 n into circularly polarized light
  • the polarization adjustment mutually similar elliptically polarized reduction Domaru is A combination of a half-wave plate rotating the plane of polarization, and a quarter-wave plate optically connected in series with the half-wave plate, instead of the quarter-wave plate 16 2
  • a plurality of light beams emitted from the optical fiber amplifier 17 1 n can be converted into linearly polarized light having the same polarization direction.
  • the series connection of the half-wave plate and the quarter-wave plate either of them may be arranged on the upstream side.
  • the light incident on the quarter-wave plate 16 2 is the light emitted from the optical fiber amplifier 17 1 n , but is emitted from a plurality of optical waveguide optical fibers. A plurality of light beams may be incident on the quarter-wave plate 16 2.
  • the optical amplification section 16 1 has 128 channels of optical paths, and a bundle—fiber is constituted by 128 optical fibers constituting the emission ends of these optical paths.
  • the number of optical paths, and thus the number of fibers forming the band roof eyer may be arbitrarily determined, and a product to which the light source device according to the present invention is applied, for example, a specification required for an exposure apparatus (on a wafer) Illuminance), and the optical performance, that is, the transmittance of the illumination optical system and the projection optical system, the conversion efficiency of the wavelength conversion unit, the output of each optical path, and the like, may be determined. Even in such a case, the control of the light amount and the exposure amount by the frequency control and the peak power control of the pulse light output from the optical modulator can be suitably applied.
  • the wavelength of the ultraviolet light it is assumed to be set to almost the same as A r F excimer laser or F 2 laser wavelength
  • the predetermined wavelength may be arbitrary, depending on the wavelength to be the setting
  • the oscillation wavelength of the laser light source 16 OA, the configuration of the wavelength conversion unit 16 3, the harmonic magnification, and the like may be determined.
  • the setting wavelength is an example.
  • the pattern may be determined according to the design rule (line width, pitch, etc.) of the pattern to be transferred onto the wafer.
  • the above-described exposure conditions, reticle type (phase shift type or not) May be considered.
  • the polarization adjusting device 16 D for aligning the polarization state of the light beam emitted from each of the optical fiber amplifiers 17 1 n with circularly polarized light (or elliptically polarized light) is provided.
  • circularly polarized light or elliptically polarized light
  • FIG. 7 shows an example of the configuration of the optical amplifying section 161 which can eliminate the need for the polarization adjusting device and the quarter-wave plate (polarization direction changing device).
  • the same reference numerals are used for the same or equivalent components as those in the above-described embodiment, and the description thereof will be omitted or simplified.
  • the optical amplifier 161 shown in Fig. 7, amplifies the pulse light from the EOM 160C described above, and periodically distributes the pulse light from the EOM 160C in chronological order. It is configured to include a branching / delaying section 167 that branches (for example, 128 branches) and a fiber amplifier 190 as a plurality of optical amplifiers.
  • the fiber amplifier 190 is composed of an amplification fiber 175 as an optical waveguide member laid in a straight line, a pumping semiconductor laser 178 for generating pump light, and the above-described output light of the EOM 160 C and a pump.
  • a WDM 179 is provided for combining the light with the light and supplying the combined light obtained to the fiber 175 for amplification. Then, the amplification fiber 175 and the WDM 179 are housed in a container 191.
  • the amplification fiber 175 is mainly composed of phosphate glass, has a core and a clad, and has two cores of Er, or Er and Yb, in a high density.
  • a doped optical fiber is used.
  • Such a phosphate glass optical fiber can be doped with a rare earth element such as Er at a higher density than a conventional silica glass optical fiber, and the fiber length required to obtain the same optical amplification factor is conventionally increased.
  • About 1/100 of the silica glass optical fiber For example, what used to be several meters to several ten meters in the past, a few centimeters to several ten centimeters is sufficient.
  • the pump light generated by the pumping semiconductor laser 178 is supplied to the amplification fiber 175 via the WDM 179 and the WDM 1
  • the pulsed light enters via 79 and travels through the core of the amplification fiber 175, stimulated radiation is generated, and the pulsed light is amplified.
  • the amplification fiber 175 is much shorter than the conventional one and has a high amplification factor, high-intensity pulse light is maintained while almost maintaining the polarization state of the pulse light at the time of incidence. Is output.
  • the length of the amplification fiber 175 is very short, the spread of the spectrum due to stimulated Raman scattering and self-phase modulation is also small.
  • the threshold value at which stimulated Raman scattering occurs when doping Er with a density of 100 times higher than that of conventional silica glass using phosphate glass, one of the factors that determine the threshold value at which stimulated Raman scattering occurs compared to conventional silica glass.
  • the Raman gain coefficient is about twice that of this, but even with this factor in mind, it is possible to output light that is about 50 times stronger than silica glass.
  • the gain per unit length can be made about 100 times, the fiber length necessary to obtain the same gain can be made about 1/100.
  • the threshold of stimulated Raman scattering Since the value can be estimated to be inversely proportional to the fiber length, by reducing the fiber length by a factor of 100, light with an intensity of about 100 times can be output without being affected by Raman scattering.
  • the spread of the spectrum due to self-phase modulation is almost proportional to the length of the amplifying fiber 175, but the length of the amplifying fiber 175 is much shorter than that of the conventional one, so the spread due to the self-phase modulation is small.
  • the spread of the vector can be suppressed sufficiently smaller than before.
  • the amplification optical fiber 175 is laid in a straight line and is housed in a substantially sealed container 191, so that the environment around the amplification optical fiber 175 is maintained substantially constant. Therefore, output light can be obtained in which the polarization state at the time of incidence is almost maintained.
  • the pumping semiconductor laser 178 generates light having a wavelength (for example, 980 nm) shorter than the oscillation wavelength of the DFB semiconductor laser 16OA as pump light. This pump light is supplied to the amplification fiber 175 via the WDM 179, thereby exciting Er and generating a so-called inverted population of energy levels. As described above, the excitation semiconductor laser 178 is controlled by the light amount control device 16C.
  • a part of the output is branched by the fiber amplifier 190, and the photoelectric conversion elements 18 provided at the respective branch ends are provided. 1 is adapted to be photoelectrically converted. Output signals of these photoelectric conversion elements 18 1 are supplied to a light quantity control device 16 C.
  • the drive of each pumping semiconductor laser 178 is performed so that the optical output from each fiber amplifier 190 is constant (that is, balanced).
  • the current is feedback-controlled.
  • the light amount control device 16C monitors the light intensity of the wavelength converter 163 based on the output signal of the photoelectric conversion element 182, and the light output from the wavelength conversion unit 163 is a predetermined light output.
  • the drive current of the semiconductor laser for excitation 178 is feedback-controlled so that
  • the amplification factor of each fiber amplifier 190 is kept constant, so that there is no uneven load between the fiber amplifiers 190 and uniform light intensity can be obtained as a whole.
  • a predetermined predetermined light intensity can be fed back to stably obtain a desired ultraviolet light output.
  • the optical amplifier of FIG. 7 can be used as it is in place of the optical amplifier of FIG. 3 described above.
  • the short amplification fiber 175 can amplify the incident light at a high amplification rate. For this reason, it is possible to supply high-intensity light to the wavelength conversion section 163 while reducing the change in the polarization state caused by passing through the amplification fiber 175.
  • the length of the path through which light passes during amplification becomes shorter, the spread of the spectrum due to stimulated Raman scattering and self-phase modulation can be suppressed. Therefore, it is possible to efficiently generate narrow-band wavelength converted light with a simple configuration.
  • the amplification fiber 175 is laid in a straight line, it is possible to prevent the occurrence of radial stress asymmetry which may cause a change in the polarization state. Almost maintained output light can be obtained.
  • the amplification fiber 175 is housed in the container 191 having a substantially closed structure, it is possible to prevent a change in the surrounding environment of the amplification fiber 175 which causes a change in the polarization state. As a result, stable wavelength conversion can be performed.
  • the main material in the above description as an amplification optical fiber 1 7 5, but using an optical fiber for mainly including Fosufei Bokuga lath, bismuth oxide-based glass (B i 2 0 3 B 2 0 3) It is also possible to use an optical fiber.
  • the bismuth oxide glass the erbium doping amount can be increased to about 100 times or more as compared with the conventional silica glass, and the same effect as in the case of the phosphate glass can be obtained.
  • an Er-doped fiber is used as the amplification fiber, but a Yb-doped fiber or another rare-earth element-doped fiber may be used.
  • the amplifying optical waveguide member is not limited to the optical fiber type member, but other members, for example, a planar waveguide type member can be used.
  • a light beam passing portion passes through a chemical filter. clean air and dry air, N 2 gas, young properly helium, argon, or to be allowed or flow filled with an inert gas krypton, becomes the light beam passage portion requires treatment true empty like.
  • the exposure apparatus of the above-described embodiment is constructed by assembling various subsystems including the respective components listed in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy.
  • various optical systems such as the illumination optical system 12 and the projection optical system PL are adjusted to achieve optical accuracy (for example, optical axis alignment) before and after this assembly.
  • Various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are adjusted to achieve electrical accuracy.
  • a high output is not required as a light source device for adjustment (for inspection), so one or a small number of fiber amplifiers 16 7 Including A light source device simplified as described above can be used.
  • the process of assembling the exposure apparatus from various subsystems includes mechanical connections, wiring connections of electric circuits, and piping connections of pneumatic circuits among the various subsystems. It goes without saying that there is an individual assembly process for each subsystem before the assembly process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure equipment is completed, comprehensive adjustments are made to ensure various precisions of the entire exposure equipment. In such an overall adjustment, the above-described simplified light source device can be used if necessary. It is desirable that the exposure apparatus be manufactured in a clean room where the temperature, cleanliness, etc. are controlled.
  • the light source device according to the present invention is used as a light source device that generates illumination light for exposure. It can also be used as a light source device for reticle alignment. In this case, it goes without saying that the above-described simplified light source device is used.
  • the light source device according to the present invention is applied to a step-and-scan type scanning exposure apparatus.
  • the light source apparatus is formed on an apparatus other than the exposure apparatus, for example, a wafer.
  • the light source device according to the present invention can also be applied to a laser repair device used for cutting a part of a circuit pattern (such as a fuse).
  • the light source device according to the present invention can be applied to an inspection device using visible light or infrared light.
  • the light source device of the present invention can be used as a light source device in an apparatus other than the exposure apparatus, for example, an optical inspection apparatus. Further, the light source device of the present invention can also be used as a light source device such as a device that corrects vision by irradiating the fundus with ultraviolet light, and various devices to which an excimer laser is applied.
  • the present invention is not limited to a step-and-scan type scanning exposure apparatus, but can be suitably applied to a stationary exposure type, for example, an exposure apparatus (eg, a stepper) of a step-and-repeat type. Further, the present invention can be applied to a step-and-stitch type exposure apparatus, a mirror projection aligner, and the like.
  • the projection optical system and the illumination optical system described in the above embodiments are merely examples, and it is a matter of course that the present invention is not limited to these.
  • the projection optical system is not limited to the refractive optical system, but may be a reflective system composed of only a reflective optical element, or a catadioptric system having a reflective optical element and a refractive optical element (power dioptric system).
  • a catadioptric system may be used as the projection optical system.
  • the reflection bending type projection optical system include, for example, Japanese Patent Application Laid-Open No. Hei 8-171504 and US Patent Nos.
  • a plurality of refractive optical elements and two mirrors are disclosed in U.S. Pat. No. 5,488,229 and Japanese Patent Application Laid-Open No. H10-1040513.
  • a catadioptric system that re-images the intermediate image of the pattern on the wafer by the primary mirror and the secondary mirror may be used.
  • a primary mirror and a secondary mirror are arranged following a plurality of refractive optical elements, and the illumination light passes through a part of the primary mirror and is reflected in the order of the secondary mirror and the primary mirror. It will reach the wafer through a portion.
  • the disclosures in the above US patents will be incorporated by reference into this description.
  • a fly-eye lens system is used as an optical integrator (homogenizer).
  • a rod integrator may be used instead.
  • the rod and integrator are arranged so that their exit surface is almost conjugate to the pattern surface of the reticle R.
  • a fixed reticle blind 30 A or a movable reticle blind 30 B may be provided.
  • the exposure equipment used for manufacturing semiconductor devices is used not only for the exposure equipment used for manufacturing semiconductor devices, but also for the manufacture of displays including liquid crystal display elements, etc., and is used for the manufacture of thin film magnetic heads and exposure equipment for transferring device patterns onto glass plates.
  • the present invention is also applicable to an exposure apparatus that transfers device patterns onto a ceramic wafer, and an exposure apparatus that is used for manufacturing an imaging device (such as a CCD), a micromachine, a DNA chip, and further, for manufacturing a reticle or a mask. can do.
  • FIG. 8 shows a flowchart of an example of manufacturing devices (semiconductor chips such as IC and LSI, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.).
  • a function and performance design of a device for example, a circuit design of a semiconductor device
  • a pattern design for realizing the function is performed.
  • step 202 mask manufacturing step
  • step 203 wafer manufacturing step
  • a wafer is manufactured using a material such as silicon.
  • step 204 wafer processing step
  • step 204 wafer processing step
  • step 205 device assembly step
  • step 205 includes, as necessary, processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation).
  • step 206 (inspection step), an operation check test, a durability test, and the like of the device manufactured in step 205 are performed. After these steps, the device is completed and shipped.
  • FIG. 9 shows a detailed flow example of the above step 204 in the case of a semiconductor device.
  • step 2 11 oxidation step
  • step 2 1 CVD step
  • step 2 13 electrode formation step
  • step 2 14 ion implantation step
  • ions are implanted into the wafer.
  • the post-processing step is executed as follows.
  • step 2 15 register forming step
  • step 2 16 exposure step
  • step 217 imaging step
  • Step 218 etching step
  • the light source device of the present invention is suitable for performing highly accurate light quantity control.
  • the wavelength stabilization control method of the present invention is suitable for setting and maintaining the center wavelength of laser light at a predetermined set wavelength.
  • the exposure apparatus and the exposure method of the present invention are suitable for forming a fine pattern on a substrate such as a wafer with high precision in a lithographic process for manufacturing a micro device such as an integrated circuit.
  • the device manufacturing method according to the present invention is suitable for manufacturing a device having a fine pattern.

Abstract

A light source (16) comprises a light producing unit (160) having a single wavelength producing light source (160A) and a light modulator (160c) for converting light from the light source to an optical pulse and outputting the optical pulse, an optical amplifying unit (161) having a group of optical fibers each provided with a fiber amplifier for amplifying the optical pulse from the light modulator, and a light intensity control unit (16c). The light intensity control unit (16c) controls stepwise the intensity of light outputted from each optical fiber by turning on/off the output separately and controls the intensity of light such as at least either the control of frequency of the optical pulse from the light modulator or the peak power thereof. Therefore it is possible to adjust minutely the intensity of light at each stage, in addition to the stepwise control of intensity of light, by controlling at least either the frequency of the optical pulse or the peak power thereof, thereby enabling the intensity of light to be controlled to any preset intensity if the intensity of light is in a predetermined range.

Description

明 細 書  Specification
光源装置及び波長安定化制御方法、 露光装置及び露光方法、 露光装置の製造 · 方法、 並びにデバイス製造方法及びデバイス 技術分野  TECHNICAL FIELD The present invention relates to a light source device and a wavelength stabilization control method, an exposure apparatus and an exposure method, a manufacturing method and an exposure apparatus, and a device manufacturing method and a device.
本発明は、 光源装置及び波長安定化制御方法、 露光装置及び露光方法、 露光 装置の製造方法、並びにデバイス製造方法及びデバイスに係り、更に詳しくは、 半導体素子、 液晶表示素子等を製造する際にリソグラフィ工程で用いられる露 光装置の露光用光源として好適な光源装置及び該光源装置に好適に適用するこ とができる波長安定化制御方法、 前記光源装置を露光用光源として備えた露光 装置及び該露光装置による露光方法、 前記露光装置の製造方法、 並びに前記露 光装置又は露光方法を用いてデバイスを製造する方法及び該デ イス製造方法 によって製造されるデバイスに関する。 背景技術  The present invention relates to a light source device and a wavelength stabilization control method, an exposure device and an exposure method, a manufacturing method of an exposure device, a device manufacturing method and a device, and more particularly, when manufacturing a semiconductor device, a liquid crystal display device, and the like. A light source device suitable as an exposure light source for an exposure device used in a lithography process, a wavelength stabilization control method that can be suitably applied to the light source device, an exposure device including the light source device as an exposure light source, The present invention relates to an exposure method using an exposure apparatus, a method for manufacturing the exposure apparatus, a method for manufacturing a device using the exposure apparatus or the exposure method, and a device manufactured by the device manufacturing method. Background art
従来より、 半導体素子(集積回路)、液晶表示素子等を製造するためのリソグ ラフイエ程では、 種々の露光装置が用いられている。 近年では、 この種の露光 装置としては、フ才卜マスク又はレチクル上に形成された微細回路パターンを、 表面にフ才卜レジス卜が塗布されたウェハ又はガラスプレー卜等の基板上に投 影光学系を介して縮小投影し、 転写する、 いわゆるステツパあるいはいわゆる スキャニング ·ステツパ等の縮小投影露光装置が、 高いスループッ卜を有する 点から主流となっている。  Conventionally, various exposure apparatuses have been used in the lithography process for manufacturing semiconductor devices (integrated circuits), liquid crystal display devices, and the like. In recent years, as this type of exposure apparatus, a fine circuit pattern formed on a mask or a reticle is projected onto a substrate such as a wafer or a glass plate having a surface coated with a photoresist. A reduction projection exposure apparatus such as a so-called stepper or a so-called scanning stepper, which performs reduction projection and transfer via an optical system, has become mainstream because of its high throughput.
しかるに、 投影露光装置等の露光装置では、 高スループットとともに高い解 像力 (解像度) が要請される。 投影露光装置の解像力 R、 焦点深度 D O Fは、 露光用照明光の波長 λ、投影光学系の開口数 Ν . Α . を用いて、次式(1 )、(2 ) によってそれぞれ表される。 However, an exposure apparatus such as a projection exposure apparatus requires a high throughput and a high resolution. The resolving power R and depth of focus DOF of the projection exposure apparatus are expressed by the following equations (1) and (2) using the wavelength λ of the exposure illumination light and the numerical aperture of the projection optical system Ν. Respectively represented by
R = K - λ/Ν. A. …… ( 1 )  R = K-λ / Ν. A. …… (1)
DOF = A/ (N. A.) 2 …… (2)  DOF = A / (N. A.) 2 …… (2)
上記の式 (1 ) から明らかなように、 解像力 R、 すなわち解像できる最小パ ターン線幅をより小さくするために、 ①比例定数 Kを小さくする、 ② N. A. を大きくする、 ③露光用照明光の波長 λを小さくする、 の 3つの方法が考えら れる。ここで、比例定数 Κは投影光学系やプロセスによって決まる定数であり、 通常 0. 5~0. 8程度の値をとる。 この定数 Κを小さくする方法は、 広い意 味での超解像と呼ばれている。 今までに、 投影光学系の改良、 変形照明、 位相 シフトレチクルなどが提案、 研究されてきた。 しかし、 適用できるパターンに 制限があるなどの難点があつた。  As is clear from the above equation (1), in order to reduce the resolution R, that is, the minimum pattern line width that can be resolved, 1) decrease the proportionality constant K, 2) increase NA, and 3) illuminating light for exposure. There are three ways to reduce the wavelength λ of. Here, the proportionality constant Κ is a constant determined by the projection optical system and the process, and usually takes a value of about 0.5 to 0.8. This method of reducing the constant Κ is called super-resolution in a broad sense. Until now, improvements and improvements in projection optics, modified illumination, and phase shift reticles have been proposed and studied. However, there were drawbacks, such as limitations on applicable patterns.
一方、 開口数 Ν. に は式 (1 ) からその値が大きいほど解像力 Rを小さく できるが、 このことは同時に式 (2) から明らかなように焦点深度 DO Fが浅 くなつてしまうことを意味する。 このため、 N. に 値は大きくするにも限界 があり、 通常は 0. 5〜0. 6程度が適当とされている。  On the other hand, for the numerical aperture Ν., From equation (1), the larger the value is, the smaller the resolution R can be. However, this also means that the depth of focus DO F becomes shallower as is clear from equation (2). means. For this reason, there is a limit to increasing the value of N. Usually, about 0.5 to 0.6 is considered appropriate.
従って、 解像力 Rを小さくする最も単純かつ有効な方法は、 露光用照明光の 波長 λを小さくすることである。  Therefore, the simplest and most effective way to reduce the resolution R is to reduce the wavelength λ of the exposure illumination light.
かかる理由により、 ステツパ等としては紫外域の輝線 (g線、 i線等) を出 力する超高圧水銀ランプを露光用光源とする g線ステツパ、 ί線ステツパが従 来主として用いられていたが、 近年ではより短波長の K r Fエキシマレーザ光 (波長 248 nm) を出力する K r Fエキシマレーザを光源とする K r Fェキ シマレーザ ·ステツパが主流となりつつある。 現在ではさらに短波長の光源と して A r Fエキシマレーザ (波長 1 93 nm) を使用する露光装置の開発が進 められている。  For this reason, g-line and x-ray steppers, which use an ultra-high pressure mercury lamp that emits ultraviolet bright lines (g-line, i-line, etc.) as a light source for exposure, have been mainly used as steppers. In recent years, a KrF excimer laser / stepper using a KrF excimer laser as a light source that outputs a shorter wavelength KrF excimer laser light (wavelength: 248 nm) is becoming mainstream. At present, the development of exposure equipment that uses an ArF excimer laser (wavelength 193 nm) as a shorter wavelength light source is underway.
しかしながら、 エキシマレーザは大型であること、 1パルスあたりのェネル ギが大きいことにより光学部品の損傷が生じやすいこと、 有毒なフッ素ガスを 使用するためレーザのメンテナンスが煩雑でかつ費用が高額となるなどの、 露 光装置の光源として不利な点が存在する。 However, excimer lasers are large, have high energy per pulse, and are liable to damage optical components, and emit toxic fluorine gas. There are disadvantages as a light source of an exposure device, such as complicated laser maintenance and high cost for use.
そこで、非線形光学結晶の非線形光学効果を利用して、長波長の光(赤外光、 可視光) をより短波長の紫外光に変換し、 こうして得られた紫外光を露光光と して使用する方法が注目されている。 こうした方法を採用した露光用光源とし ては、 例えば特開平 8— 3 3 4 8 0 3号公報に開示されているような、 半導体 レーザを備えたレーザ光発生部からの光を、 波長変換部に設けた非線形光学結 晶により波長変換し、 紫外光を発生させる 1つのレーザ要素を、 複数本マ卜リ ックス状 (例えば 1 0 X 1 0 ) に束ねて一つの紫外光源とするアレイレーザな どが知られている。  Therefore, using the nonlinear optical effect of the nonlinear optical crystal, long-wavelength light (infrared light and visible light) is converted to shorter-wavelength ultraviolet light, and the resulting ultraviolet light is used as exposure light. The way to do it is attracting attention. As a light source for exposure employing such a method, for example, a light from a laser light generating section provided with a semiconductor laser, as disclosed in Japanese Patent Application Laid-Open No. 8-334483, is used. An array laser, which combines a single laser element that generates wavelengths by converting the wavelength with a nonlinear optical crystal provided in the Which is known.
このアレイレーザでは、 個々に独立なレーザ要素を複数本束ねることによつ て、 個々のレーザ要素の光出力を低く押さえつつ、 装置全体の光出力を高出力 とすることができる。 しかし、 個々のレーザ要素が独立していることから、 各 レーザ要素の発振スぺク卜ルを一致させるためには、 微妙な調整を必要とし、 かつ非常に複雑な構成を採用することが必要であった。  In this array laser, by bundling a plurality of independent laser elements, the optical output of the entire apparatus can be increased while the optical output of each laser element is kept low. However, since the individual laser elements are independent, it is necessary to make fine adjustments and to adopt a very complicated configuration in order to match the oscillation spectrum of each laser element. Met.
そこで、 レーザ発振源を〗つとし、 このレーザ発振源から射出されたレーザ 光を分岐するとともに、 各分岐光を増幅した後、 共通の非線形光学結晶で波長 変換する方法が考えられる。 この方法を採用する場合、 レーザ光の引き回しに は光フアイバを使用することが便宜であり、 非線型光学結晶へは束ねられた複 数の光ファイバから射出された複数の光束を入射させる構成が、構造の簡単さ、 出力ビー厶径小型化、 メンテナンス性の観点から最適である。  Therefore, a method is conceivable in which one laser oscillation source is used, the laser light emitted from this laser oscillation source is branched, and each branched light is amplified and then wavelength-converted by a common nonlinear optical crystal. When this method is adopted, it is convenient to use an optical fiber to route the laser light, and a configuration is used in which a plurality of light beams emitted from a plurality of bundled optical fibers are incident on the nonlinear optical crystal. Optimum from the viewpoint of simplicity of structure, miniaturization of output beam diameter, and maintainability.
また、 非線形光学結晶を使用して、 非線形光学効果により 2倍高調波等を効 率良く発生させるためには、 非線型光学結晶の結晶方向に応じた特定の方向の 直線偏光を非線型光学結晶に入射させることが必要である。 しかし、 複数の光 ファイバから射出される直線偏光の方向を揃えることは、 一般に困難である。 これは、 例え偏波面保持ファイバを使用し、 直線偏光を導波した場合であって も光ファイバはほぼ円形の断面形状を有しているので、 光ファイバの外形形状 からは、 直線偏光の方向を特定することができないからである。 Also, in order to use the nonlinear optical crystal to efficiently generate second harmonics and the like by the nonlinear optical effect, it is necessary to convert the linearly polarized light in a specific direction according to the crystal direction of the nonlinear optical crystal to the nonlinear optical crystal. It is necessary to make the incident light. However, it is generally difficult to align the directions of linearly polarized light emitted from a plurality of optical fibers. This is the case when a polarization maintaining fiber is used and linearly polarized light is guided. Also, since the optical fiber has a substantially circular cross-sectional shape, the direction of linearly polarized light cannot be specified from the external shape of the optical fiber.
また、 周知の如く、 上述したような短波長域のエキシマレーザ光を使用した 場合、 主として材料の透過率の問題から、 投影光学系のレンズに利用できる素 材は現時点では合成石英、 ホタル石、 あるいはフッ化リチウム等のフッ化物結 晶等の材料に限られている。  Also, as is well known, when excimer laser light in the short wavelength region as described above is used, the material that can be used for the lens of the projection optical system is currently synthetic quartz, fluorite, Alternatively, it is limited to materials such as fluoride crystals such as lithium fluoride.
しかし、 投影光学系にこのような石英ゃホタル石等のレンズを使用した場合 には、 実質的に色収差の補正が難しいので、 色収差の発生による結像性能の劣 化を防ぐために、 エキシマレーザ光の発振スペクトル幅を狭める、 いわゆる波 長の狭帯域化が必要となる。 この波長の狭帯域化は、 例えばレーザ共振器に設 けられた狭帯域化モジュール (例えばプリズムとグレーティング (回折格子) とを組み合わせたものや、 エタロン等の光学素子が用いられる) を使用して行 われ、 露光中投影光学系に供給されるエキシマレーザ光の波長のスぺク卜ル幅 を常に所定の波長幅に収めると同時に、 その中心波長を所定の波長に維持する ための、 いわゆる波長安定化の制御が必要となる。  However, when such a lens made of quartz or fluorite is used for the projection optical system, it is practically difficult to correct the chromatic aberration. Therefore, in order to prevent the deterioration of the imaging performance due to the occurrence of the chromatic aberration, the excimer laser beam is used. Therefore, it is necessary to narrow the oscillation spectrum width, that is, to narrow the bandwidth of the wavelength. The narrowing of the wavelength can be achieved, for example, by using a narrowing module (for example, a combination of a prism and a grating (diffraction grating) or an optical element such as an etalon) provided in a laser resonator. The so-called wavelength is used to keep the spectral width of the wavelength of the excimer laser light supplied to the projection optical system during exposure to a predetermined wavelength width, and to maintain the center wavelength at the predetermined wavelength at the same time. Stabilization control is required.
上記の波長安定化の制御を実現するためには、 エキシマレーザ光の光学特性 (中心波長及びスペクトル半値幅等) をモニタする必要がある。 エキシマレー ザ装置の波長モニタ部は、 一般にフアブリペロー分光器であるファブリベロ 一 -ェタロン (Fabry-Perot etalon:以下、 「エタロン素子」 ともいう) を中心 として構成されている。  In order to realize the above-mentioned control of wavelength stabilization, it is necessary to monitor the optical characteristics of the excimer laser light (center wavelength, spectral half width, etc.). The wavelength monitor section of an excimer laser device is generally configured around a Fabry-Perot etalon (hereinafter, also referred to as an “etalon element”), which is a Fabry-Perot spectrometer.
また、 半導体素子の高集積化に伴いパターン線幅がますます微細化し、 ステ ツバ等の露光装置には、 露光精度、 例えばマスクと基板との重ね合せ精度のま すますの向上が求められるようになつてきた。 この重ね合せ精度は投影光学系 のディス ! ^一ション成分等の収差を如何に抑えるかに左右される。 このため、 露光装置には、 露光用照明光の中心波長の安定性及びますますの狭帯域化が求 められるようになってきた。 この内、 狭帯域化に対処する手法としては、 レー ザ光源そのものとして、 単一波裊光源を採用することが考えられる。 In addition, the pattern line width is becoming increasingly finer as semiconductor devices become more highly integrated. It has become. The overlay accuracy depends on how to suppress aberrations such as distortion components of the projection optical system. For this reason, the exposure apparatus has been required to have stability in the center wavelength of the illumination light for exposure and an increasingly narrower band. Among them, as a method to cope with the narrow band, It is conceivable to adopt a single-wavelength light source as the light source itself.
一方、 投影光学系は所定の露光波長にのみ合わせて調整されているため、 中 心波長を安定に維持できなければ、結果的に投影光学系の色収差が発生したり、 投影光学系の倍率、 ディストーション及びフオーカス等の結像特性が変動して しまうため、 中心波長の安定性を維持することは必要不可欠である。  On the other hand, since the projection optical system is adjusted only to the predetermined exposure wavelength, if the center wavelength cannot be stably maintained, chromatic aberration of the projection optical system will result, Maintaining the stability of the center wavelength is indispensable because the imaging characteristics such as distortion and focus fluctuate.
しかしながら、 エタ口ン素子はエタ口ン雰囲気の溫度ゃ圧力の影響を受ける ため、 エタ口ン雰囲気の温度変動や大気圧変動の影響が無視出来なくなる。 また、 デバイスルール (実用最小線幅) は、 将来的にますます微細化するこ とは確実であり、 次世代の露光装置ではますます高い重ね合わせ精度が要求さ れる。 この重ね合わせ精度は、 例えばディストーション成分を如何に抑えるか に左右される。 また、 焦点深度の増大の為には、 U D O F (ユーザブル D O F ) の増化及びフォーカスの安定性が必要になる。 いずれも、 高度な中心波長の安 定性及びスぺクトル半値幅の制御性が要求される。  However, the influence of the temperature and atmospheric pressure fluctuations in the atmosphere of the ethanol cannot be ignored since the element of the atmosphere is affected by the temperature and pressure of the atmosphere in the atmosphere. In addition, device rules (practical minimum line width) will surely become even finer in the future, and next-generation lithography equipment will require even higher overlay accuracy. The overlay accuracy depends on, for example, how to suppress distortion components. Also, in order to increase the depth of focus, it is necessary to increase U D OF (usable D OF) and stabilize the focus. In each case, high stability of the central wavelength and controllability of the spectrum half width are required.
また、 露光装置にはウェハ毎のレジス卜感度等の違いにあわせた露光量制御 性能を実現することが求められ、 広いダイナミックレンジ、 典型的には 1〜1 / 7程度が求められる。 従来のエキシマレーザを光源とする露光装置では、 上 記のウェハ毎のレジスト感度等の違いにあわせた露光量制御のために、 例えば N Dフィルタ等のエネルギ粗調器が用いられている。  In addition, an exposure apparatus is required to realize an exposure amount control performance adapted to a difference in a resist sensitivity or the like for each wafer, and a wide dynamic range, typically about 1 to 1/7 is required. In a conventional exposure apparatus using an excimer laser as a light source, an energy rough adjuster such as an ND filter is used for controlling the exposure amount according to the above-described difference in resist sensitivity or the like for each wafer.
しかしながら、 かかる手法による場合には、 透過率が較正された N Dフィル 夕が必要であり、 N Dフィルタの耐久性、 透過率の経時変化も問題になる。 さ らに、 最大光量の 1 Z 7の露光量しか必要としない場合でも、 エキシマレーザ は最大出力強度で動作し、 出力光の 6 Z 7は露光には使用されず無駄になる。 また、 光学部品消耗、 消費電力の点でも難点があった。  However, in the case of using such a method, an ND filter whose transmittance is calibrated is required, and the durability of the ND filter and the change with time of the transmittance also become problems. Furthermore, even when only the maximum light exposure of 1Z7 is required, the excimer laser operates at the maximum output intensity, and the output light 6Z7 is not used for exposure and is wasted. There were also disadvantages in terms of optical component consumption and power consumption.
現状の露光装置には、 上記のウェハ毎のレジス卜感度等の違いにあわせた光 量制御性能 (以下、 適宜 「第 1の露光量制御性能」 と呼ぶ) の他、 同一ウェハ 内におけるショット領域 (チップ) 毎のプロセスばらつきを補正する露光量制 御性能 (以下、 適宜 「第 2の露光量制御性能」 と呼ぶ) が要求される。 また、 スキャニング ·ステツバの場合には、 ショッ卜領域内の線幅均一性を実現する ための露光量制御性能 (以下、 適宜 「第 3の露光量制御性能」 と呼ぶ) が更に 要求される。 The current exposure apparatus has a light amount control performance (hereinafter, appropriately referred to as a “first exposure amount control performance”) according to the above-described differences in the resist sensitivity for each wafer, as well as a shot area within the same wafer. (Exposure amount system) to correct process variation for each (chip) Control performance (hereinafter referred to as “second exposure control performance” as appropriate). Further, in the case of the scanning step, an exposure amount control performance (hereinafter, appropriately referred to as “third exposure amount control performance”) for realizing line width uniformity in the shot area is further required.
現状の露光装置では、 上記の第 2の露光量制御性能として、 ダイナミックレ ンジが設定露光量の ± 1 0 %程度、 ショット間ステッピング時間である 1 0 0 m s程度の時間内に設定値に制御すること、 制御精度として設定露光量の士 1 %程度が要求されている。  In the current exposure system, the dynamic range is controlled to the set value within about ± 10% of the set exposure amount and the shot-to-shot stepping time of about 100 ms as the second exposure amount control performance described above. The required control accuracy is about 1% of the set exposure.
また、 上記第 3の露光量制御性能としては、 制御精度として典型的には 1シ ョッ卜の露光時間である 2 0 m s e cの時間内に設定露光量の ± 0 . 2 %に設 定すること、 制御速度 1 m s程度が要求されている。  As the third exposure amount control performance, the control accuracy is typically set to ± 0.2% of the set exposure amount within a time period of 20 msec, which is an exposure time of 1 shot. A control speed of about 1 ms is required.
従って、 露光装置の光源として、 上記第 1〜第 3の露光量制御性能を実現す るためにも、 制御に必要な要請に応じた制御を行うことができる光源装置の出 現が期待されている。 ここで、制御に必要な要請とは、 (a )制御のダイナミツ クレンジ、 (b )制御精度、 (c )制御速度、 (d )検出光強度と制御量とのリニ ァリティの程度、 (e ) 省電力を目的とするエネルギセイブの機能等である。 本発明は、 かかる事情の下になされたもので、 その第 1の目的は、 上記の制 御に必要な要請に応じた光量制御を行うことができる光源装置を提供すること にある。  Therefore, in order to realize the above-described first to third exposure amount control performances, a light source device capable of performing control according to a request required for control is expected as a light source of an exposure device. I have. Here, the requirements required for control include (a) dynamic range of control, (b) control accuracy, (c) control speed, (d) degree of linearity between detected light intensity and control amount, and (e) This is an energy save function for power saving. The present invention has been made under such circumstances, and a first object of the present invention is to provide a light source device that can perform light amount control according to a request necessary for the above control.
本発明の第 2の目的は、 レーザ光の中心波長を所定の設定波長に確実に維持 することができる光源装置を提供することにある。  A second object of the present invention is to provide a light source device that can reliably maintain the center wavelength of laser light at a predetermined set wavelength.
本発明の第 3の目的は、 簡単な構成で偏光状態を制御しつつ所定の光を発生 することができる光源装置を提供することにある。  A third object of the present invention is to provide a light source device capable of generating predetermined light while controlling the polarization state with a simple configuration.
本発明の第 4の目的は、 レーザ光の中心波長を所定の設定波長に確実に維持 することができる波長安定化制御方法を提供することにある。  A fourth object of the present invention is to provide a wavelength stabilization control method that can reliably maintain the center wavelength of laser light at a predetermined set wavelength.
本発明の第 5の目的は、 要求される露光量制御を容易に実現することができ る露光装置を提供することにある。 The fifth object of the present invention is to easily realize required exposure amount control. An exposure apparatus is provided.
本発明の第 6の目的は、 雰囲気の温度変動等に影響されず、 高精度な露光を 行うことができる露光装置を提供することにある。  A sixth object of the present invention is to provide an exposure apparatus that can perform high-precision exposure without being affected by a change in the temperature of the atmosphere.
本発明の第 7の目的は、 感光剤の感度特性の変化によらず精度良く露光を行 うことができる露光装置を提供することにある。  A seventh object of the present invention is to provide an exposure apparatus capable of performing exposure with high accuracy regardless of a change in sensitivity characteristics of a photosensitive agent.
本発明の第 8の目的は、 効率的に所定のバターンを基板に転写することがで きる露光装置を提供することにある。  An eighth object of the present invention is to provide an exposure apparatus capable of efficiently transferring a predetermined pattern onto a substrate.
本発明の第 9の目的は、 要求される露光量制御を容易に実現することができ る露光方法を提供することにある。  A ninth object of the present invention is to provide an exposure method capable of easily achieving required exposure amount control.
本発明の第 1 0の目的は、 雰囲気の温度変動等に影響されず、 高精度な露光 を行うことができる露光方法を提供することにある。  A tenth object of the present invention is to provide an exposure method capable of performing high-precision exposure without being affected by temperature fluctuations of the atmosphere.
本発明の第 1 1の目的は、 高集積度のマイクロデバイスの生産性を向上する ことができるデバイス製造方法を提供することにある。 発明の開示  A first object of the present invention is to provide a device manufacturing method capable of improving the productivity of a highly integrated microdevice. Disclosure of the invention
本発明は、 第 1の観点からすると、 単一波長の光を発生する光源装置であつ て、 単一波長の光を発生する光発生部と;前記光発生部の出力段に並列に配置 された複数の光ファイバから成るファイバ群と;前記各光ファイバからの光出 力を個別にオン ·オフすることにより前記ファイバ群から出力される光の光量 を制御する光量制御装置と;を備える第 1の光源装置である。  According to a first aspect of the present invention, there is provided a light source device for generating light of a single wavelength, comprising: a light generating unit for generating light of a single wavelength; and a light source unit arranged in parallel at an output stage of the light generating unit. A fiber group consisting of a plurality of optical fibers; and a light amount control device for controlling the light amount of light output from the fiber group by individually turning on and off the light output from each of the optical fibers. 1 is a light source device.
これによれば、 光発生部で発生した単一波長の光が、 その出力段に並列に配 置されたファイバ群を構成する複数の光ファイバのそれぞれに向かって進むが、 光量制御装置では各光ファイバからの光出力を個別にオン ·オフすることによ リファイバ群から出力される光の光量を制御する。 このように本発明では、 フ アイバ群を構成する各光ファイバの光出力を個別にオン ·オフするという簡単 な手法によりファイバ群から出力される光の光量制御を実現することができる とともに、 光フアイバの数に比例した複数段階の光量制御が可能となるので、 広いダイナミックレンジを容易に実現することができる。 この場合、 各光ファ ィバの諸性能 (ファイバ径等を含む) は異なっていても良いが、 各光ファイバ の諸性能がほぼ同じである場合には、 光ファイバのそれぞれからの同一光量の 光を出力させることができる結果、 光ファイバの数 Nに応じた N段階の光量制 御を正確かつ確実に実行することができる。 従って、 例えば、 N≥1 0 0とす れば、 1 %刻み以下の精度で光量を制御することができる。 この場合、 制御量 と光量とのリニアリティの程度も良い。 勿論、 この場合、 N Dフィルタ等のェ ネルギ粗調器は不要となるので、 該フィルタの耐久性、 透過率の経時変化等に 起因する光量制御性能の劣化等の諸問題も改善できる。 According to this, light of a single wavelength generated by the light generation unit travels toward each of a plurality of optical fibers constituting a group of fibers arranged in parallel at its output stage. By individually turning on and off the optical output from the optical fiber, the amount of light output from the group of optical fibers is controlled. As described above, according to the present invention, it is possible to realize the light amount control of the light output from the fiber group by a simple method of individually turning on and off the optical output of each optical fiber constituting the fiber group. At the same time, a plurality of levels of light quantity control in proportion to the number of optical fibers can be performed, so that a wide dynamic range can be easily realized. In this case, the performances (including the fiber diameter etc.) of each optical fiber may be different, but if the performances of each optical fiber are almost the same, the same amount of light from each of the optical fibers As a result of being able to output light, N-level light quantity control according to the number N of optical fibers can be executed accurately and reliably. Therefore, for example, if N≥100, the light amount can be controlled with an accuracy of 1% or less. In this case, the degree of linearity between the control amount and the light amount is good. Of course, in this case, since an energy coarse adjuster such as an ND filter is not required, various problems such as deterioration of the light quantity control performance due to durability of the filter, a change with time in transmittance, and the like can be improved.
この場合において、 前記ファイバ群を構成する前記複数の光ファイバは、 そ れぞれの少なくとも出力端部が束ねられてバンドル—ファイバが構成されてい ても良い。 通常、 光ファイバの径は細いので、 1 0 0本以上束ねても直径が数 m m程度以内に収めることができ、 そのバンドル一ファイバの出力段に何らか の光学素子、 例えば、 四分の一波長板や波長変換器を構成する非線形光学結晶 等の光学素子を配置する場合に、 小型の光学素子を配置できる。  In this case, the plurality of optical fibers constituting the fiber group may be bundled at least at their output ends to form a bundle-fiber. In general, the diameter of an optical fiber is small, so that even if 100 or more fibers are bundled, the diameter can be kept within several mm, and some optical element, for example, a quarter When arranging an optical element such as a nonlinear optical crystal constituting a wave plate or a wavelength converter, a small optical element can be arranged.
本発明の第 1の光源装置では、 各光ファイバからの光出力をオン ·オフする 手法は、 例えば、 各光ファイバに対する入射光を遮光する機械的又は電気的な シャツ夕、 あるいは各光ファイバからの光の出射を阻止する機械的又は電気的 なシャツタを設ける等種々考えられるが、 例えば、 前記各光ファイバを含んで 構成される各光経路の一部に、 光増幅を行うことができるファイバ増幅器が少 なくとも 1段設けられている場合には、 前記光量制御装置は、 前記各光フアイ バからの前記光出力のオン ·オフを前記ファイバ増幅器の励起用光源からの励 起光の強度の切り換えにより行うこととしても良い。  In the first light source device of the present invention, the method of turning on / off the light output from each optical fiber includes, for example, a mechanical or electrical shirt that blocks incident light to each optical fiber, or There are various possibilities, such as providing a mechanical or electrical shutter that blocks the emission of light.For example, a fiber that can perform optical amplification is provided in a part of each optical path that includes the optical fiber. In the case where at least one amplifier is provided, the light quantity control device controls the on / off of the optical output from each of the optical fibers by changing the intensity of the excitation light from the excitation light source of the fiber amplifier. The switching may be performed.
ここで、 「各光ファイバを含んで構成される各光経路の一部に、光増幅を行う ことができるファイバ増幅器が少なくとも 1段設けられている」 とは、 各光経 路が光ファイバとは別にその入力段に設けられた光増幅器を有している場合、 各光経路を構成する光ファイバの一部がファイバ増幅器となっている場合のい ずれをも含む。 Here, “at least one stage of fiber amplifier capable of performing optical amplification is provided in a part of each optical path including each optical fiber” means that each optical path When the optical path has an optical amplifier provided at the input stage separately from the optical fiber, this includes any case where a part of the optical fiber constituting each optical path is a fiber amplifier.
かかる場合には、 フアイバ増幅器により各光フアイバを含む光経路に入射し た光を増幅できるとともに、 光出力をオフすることとされた光ファイバを含む 光経路に設けられた光増幅器に対する励起光の強度レベルが低く (零を含む) 設定されるので、 その分省エネが可能である。 また、 ファイバ増幅器の励起用 光源からの励起光の強度の切り換えにより光出力のオン ·オフを行うので、 シ ャッタ等を用いる場合に比べて短時間で光出力のオン ·オフが可能である。 本発明の第 1の光源装置では、 各光ファイバからの前記光出力のオン ·オフ を前記ファイバ増幅器の励起用光源からの励起光の強度の切り換えにより行う 場合に、 励起光の強度レベルの切り換えは、 所定範囲内の固定的でない 2つの レベル間で行っても良いが、 前記光量制御装置は、 前記励起用光源からの励起 光の強度を所定レベルと零レベルとのいずれかに択一的に設定することにより 前記励起光の強度の切り換えを行うこととしても良い。 かかる場合、 前記光量 制御装置は、 前記励起用光源をオン ·オフすることにより、 前記励起光の強度 を所定レベルと零レベルとのいずれかに択一的に設定することとしても良い。 本発明の第 1の光源装置では、 各光ファイバからの前記光出力のオン ·オフ を前記ファイバ増幅器の励起用光源からの励起光の強度の切り換えにより行う 場合に、 前記光量制御装置は、 前記励起用光源からの励起光の強度を所定の第 1 レベルと該第 1 レベルより小さい第 2レベルとのいずれかに択一的に設定す ることにより前記励起光の強度の切り換えを行うこととしても良い。すなわち、 ファイバ増幅器では、 励起光の強度を零にしなくても所定量以下にすると、 光 の吸収が生じて、 ファイバ増幅器からの出射光強度は殆ど零となるので、 励起 用光源からの励起光の強度を所定の第 1 レベルと該第 1 レベルより小さい第 2 レベルとのいずれかに択一的に設定することにより、 光ファイバからの光出力 をオン ·オフすることができる。 この場合も第 1 レベル、 第 2レベルは所定範 囲内の固定的でない 2つのレベルであっても良い。 In such a case, the light incident on the optical path including each optical fiber can be amplified by the fiber amplifier, and the pumping light for the optical amplifier provided in the optical path including the optical fiber whose optical output is turned off is turned off. Since the intensity level is set low (including zero), energy saving is possible. Further, since the light output is turned on and off by switching the intensity of the pump light from the pump light source of the fiber amplifier, the light output can be turned on and off in a shorter time than when a shutter or the like is used. In the first light source device of the present invention, when the on / off of the optical output from each optical fiber is performed by switching the intensity of the excitation light from the excitation light source of the fiber amplifier, the intensity level of the excitation light is switched. May be performed between two non-fixed levels within a predetermined range, but the light amount control device may selectively set the intensity of the excitation light from the excitation light source to a predetermined level or a zero level. The intensity of the excitation light may be switched by setting to. In such a case, the light quantity control device may set the intensity of the excitation light to one of a predetermined level and a zero level by turning on and off the excitation light source. In the first light source device of the present invention, when the on / off of the optical output from each optical fiber is performed by switching the intensity of the excitation light from the excitation light source of the fiber amplifier, the light amount control device includes: By setting the intensity of the excitation light from the excitation light source to one of a predetermined first level and a second level smaller than the first level, the intensity of the excitation light is switched. Is also good. That is, in a fiber amplifier, if the intensity of the pump light is not more than zero, if the intensity is not more than a predetermined value, light absorption occurs, and the intensity of the light emitted from the fiber amplifier becomes almost zero. By selectively setting the intensity of the optical fiber to one of a predetermined first level and a second level smaller than the first level, the optical output from the optical fiber Can be turned on / off. Also in this case, the first level and the second level may be two non-fixed levels within a predetermined range.
本発明の第 1の光源装置では、 前記各光経路に、 前記ファイバ増幅器が複数 段設けられている場合、 前記光量制御装置は、 前記各光ファイバからの前記光 出力のオン ·オフを最終段のファイバ増幅器の励起用光源からの励起光の強度 の切り換えにより行うこととしても良い。 かかる場合には、 最終段以外のファ ィバ増幅器の励起用光源からの励起光の強度を切り換える場合に問題となる A S E (Ampl i f ied Spontaneous Emi ss ion,自然放出光) の悪影響を回避すること ができるとともに、 後段のファイバ程大きな励起光の強度を必要とするので光 ファイバからの光出力をオフしたときの励起用光源の省エネの効果が一層大き くなる。  In the first light source device of the present invention, when a plurality of stages of the fiber amplifiers are provided in each of the optical paths, the light amount control device turns on / off the light output from each of the optical fibers in a final stage. This may be performed by switching the intensity of the excitation light from the excitation light source of the fiber amplifier. In such a case, avoid the adverse effect of ASE (Amplified Spontaneous Emission), which is a problem when switching the intensity of the pump light from the pump light source of the fiber amplifier other than the last stage. In addition to the above, the later fiber requires higher pumping light intensity, so that the power saving effect of the pumping light source when the light output from the optical fiber is turned off is further increased.
この場合において、 前記最終段の前記ファイバ増幅器は、 他の段のファイバ 増幅器に比べてモードフィールド径が大きいことが望ましい。かかる場合には、 光ファイバ中での非線形効果による増幅光のスぺク卜ル幅の増加を避けること ができる。  In this case, it is desirable that the fiber amplifier of the last stage has a larger mode field diameter than the fiber amplifiers of the other stages. In such a case, an increase in the spectrum width of the amplified light due to the non-linear effect in the optical fiber can be avoided.
本発明の第 1の光源装置では、 前記各光ファイバからの光出力のオン ·オフ 状況に対応する出力強度マップが予め記憶された記憶装置を更に備え、 前記光 量制御装置は、 前記出力強度マップと所定の設定光量に基づいて前記各光ファ ィバからの光出力を個別にオン ·オフすることとしても良い。かかる場合には、 各光ファイバの出力にばらつきがあってもファイバ群の光出力を設定光量にほ ぼ一致させることができるとともに、 諸性能の異なる光ファイバを用いること も可能となる。  The first light source device of the present invention further includes a storage device in which an output intensity map corresponding to the on / off status of the optical output from each of the optical fibers is stored in advance, and the light intensity control device includes: The light output from each of the optical fibers may be individually turned on / off based on a map and a predetermined set light amount. In such a case, even if there is a variation in the output of each optical fiber, the optical output of the fiber group can be made substantially equal to the set light amount, and optical fibers having various performances can be used.
この場合において、 前記出力強度マップは、 予め測定された各ファイバ出力 のばらつきに基づいて作成されていることが望ましい。 かかる場合には予め実 際に測定された各ファイバ出力のばらつきに基づいて出力強度マップが作成さ れているので、 ファイバ群の光出力を設定光量に確実に一致させることができ る。 In this case, it is preferable that the output intensity map is created based on the dispersion of each fiber output measured in advance. In such a case, since the output intensity map is created based on the dispersion of each fiber output actually measured in advance, the light output of the fiber group can be surely matched with the set light amount. You.
本発明の第 1の光源装置では、 前記各光ファイバから出力される前記光の波 長を変換する波長変換部を更に備える場合には、 前記出力強度マップは、 予め 測定された前記各ファイバ出力に対応する波長変換効率のばらつきに起因する 出力のばらつきを更に考慮して作成されていることが望ましい。 かかる場合に は、 各光ファイバからの光出力に対する波長変換効率にばらつきがあっても、 出力光の光量を設定光量に制御することができる。  In the first light source device of the present invention, when further including a wavelength conversion unit that converts a wavelength of the light output from each of the optical fibers, the output intensity map is obtained by measuring the fiber output measured in advance. It is desirable that the power supply should be created in further consideration of the output variation caused by the wavelength conversion efficiency variation corresponding to the above. In such a case, even if the wavelength conversion efficiency with respect to the optical output from each optical fiber varies, the amount of output light can be controlled to the set amount.
この場合において、 前記光発生部は、 赤外域から可視域までの範囲内の単一 波長のレーザ光を発生し、 前記波長変換部は、 前記レーザ光の高調波である紫 外光を出力することとしても良い。 例えば、 前記光発生部は、 波長〗 . 5 m 付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 / m 付近の前記レーザ光の 8倍高調波及び 1 0倍高調波のいずれかを発生すること とすることができる。  In this case, the light generation unit generates a single-wavelength laser light within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser light. It is good. For example, the light generation unit generates a single-wavelength laser light having a wavelength of about 0.5 m, and the wavelength conversion unit generates an eighth harmonic and a 1st harmonic of the laser light having a wavelength of about 1.5 / m. Either of the 0th harmonic can be generated.
本発明の第 1の光源装置では、 前記各光ファイバから出力される前記光の波 長を変換する波長変換部を更に備えていても良い。 かかる場合には、 波長変換 部出力は、 光出力がオンであるファイバ数に比例する。 このため、 例えば、 各 光フアイバの諸性能がほぼ同じである場合には、 光フアイバのそれぞれから同 一光量の光を出力させることができる結果、 リニアリティ良く光量を制御する ことができる。  The first light source device of the present invention may further include a wavelength converter for converting a wavelength of the light output from each of the optical fibers. In such a case, the output of the wavelength converter is proportional to the number of fibers whose optical output is on. For this reason, for example, when the performances of the respective optical fibers are substantially the same, the same amount of light can be output from each of the optical fibers. As a result, the amount of light can be controlled with good linearity.
この場合において、 前記光発生部は、 赤外域から可視域までの範囲内の単一 波長のレーザ光を発生し、 前記波長変換部は、 前記レーザ光の高調波である紫 外光を出力することとしても良い。 例えば、 前記光発生部は、 波長 1 . 5 t m 付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 m 付近の前記レーザ光の 8倍高調波及び 1 0倍高調波のいずれかを発生すること とすることができる。  In this case, the light generation unit generates a single-wavelength laser light within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser light. It is good. For example, the light generating section generates a single-wavelength laser light having a wavelength of about 1.5 tm, and the wavelength converting section generates an eighth harmonic of the laser light having a wavelength of about 1.5 m and 10 times higher. Any of the harmonics can be generated.
本発明の第 .1の光源装置では、 前記光発生部が、 単一波長の光を発生する光 源と、 前記光源からの光を所定周波数のパルス光に変換して出力する光変調器 とを有する場合には、 前記光量制御装置は、 前記光変調器から出力されるパル ス光の周波数及びピークパワーの少なくとも一方を更に制御することとしても 良い。 かかる場合には、 光ファイバ群を構成する各ファイバの光出力の個別才 ン ·オフによる段階的な光量制御に加えて、 各段階間の光量の微調整が光変調 器から出力されるパルス光の周波数及びピークパワーの少なくとも一方の制御 により可能になるので、 結果的に光量の連続制御が可能となり、 所定範囲内で あれば設定露光量が如何なる値に設定されても、 出力光の光量をその設定光量 に一致させることが可能になる。 In the light source device according to the first aspect of the present invention, the light generating unit generates light having a single wavelength. A light source, and a light modulator that converts the light from the light source into a pulsed light having a predetermined frequency and outputs the pulsed light. At least one of the peak powers may be further controlled. In such a case, in addition to the stepwise light amount control by individually turning on and off the light output of each fiber constituting the optical fiber group, fine adjustment of the light amount between each step is performed by the pulse light output from the optical modulator. Control is possible by controlling at least one of the frequency and the peak power, and consequently the light amount can be continuously controlled.If the set exposure amount is set to any value within the predetermined range, the output light amount can be reduced. It is possible to match the set light quantity.
本発明の第 1の光源装置では、 前記複数の光ファイバそれぞれからの光出力 を個別に遅延させて、 前記光出力を時間的にずらして行わせる遅延部を更に備 えていても良い。 かかる場合には、 各光ファイバから出力される光が時間的に 重なることがなくなるので、 結果的に空間的コヒーレンシ一を低減することが 可能になる。  The first light source device of the present invention may further include a delay unit that individually delays the optical output from each of the plurality of optical fibers and shifts the optical output in time. In such a case, the lights output from the optical fibers do not overlap with each other in time, so that spatial coherency can be reduced as a result.
本発明の第 1の光源装置では、 前記光発生部が、 レーザ光を発振するレーザ 光源を有する場合には、 前記レーザ光の中心波長を所定の設定波長に維持する ための波長安定化に関連する前記レーザ光の光学特性をモニタするビー厶モニ 夕機構と;前記ビームモニタ機構の検出基準波長の温度依存性のデータに基づ いて、 波長キャリブレーションを行う波長キャリブレーション制御装置と;を 更に備えることとすることができる。 かかる場合には、 波長キヤリブレーショ ン制御装置により、 ビームモニタ機構の検出基準波長の温度依存性のデータに 基づいて、 波長キャリブレーションが行われるので、 ビームモニタ機構の検出 基準波長を設定波長に正確に設定することができ、 これによりビームモニタ機 構の雰囲気の温度等が変動しても、 それに影響を受けることなく、 ビー厶モニ 夕機構を用いてレーザ光の中心波長を所定の設定波長に確実に維持するような 波長安定化制御が可能になる。 従って、 より高精度な光量制御が可能となる。 この場合において、 前記複数の光ファイバを介した同一波長の複数の光束の 偏光状態を揃える偏光調整装置と;前記複数の光ファイバを介した全ての光束 を同一の偏光方向を有する複数の直線偏光光束に変換する偏光方向変換装置 と;を更に備えることとすることができる。 In the first light source device of the present invention, when the light generation unit has a laser light source that oscillates laser light, the light generation unit relates to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength. A beam monitor mechanism for monitoring the optical characteristics of the laser light, and a wavelength calibration control device for performing wavelength calibration based on the temperature dependence data of the detection reference wavelength of the beam monitor mechanism. Can be provided. In such a case, the wavelength calibration controller performs the wavelength calibration based on the data on the temperature dependence of the detection reference wavelength of the beam monitor mechanism, so that the detection reference wavelength of the beam monitor mechanism is set to the set wavelength. It is possible to set the center wavelength of the laser light to a predetermined wavelength using the beam monitor mechanism without being affected by fluctuations in the temperature of the atmosphere of the beam monitor mechanism. Wavelength stabilization control that can be reliably maintained. Therefore, more accurate light quantity control becomes possible. In this case, a polarization adjusting device for aligning the polarization states of a plurality of light beams having the same wavelength through the plurality of optical fibers; and a plurality of linearly polarized lights having the same polarization direction for all the light beams through the plurality of optical fibers. A polarization direction conversion device for converting the light into a light flux.
この場合において、 前記各光ファイバを含んで構成される各光経路の一部に は、 光増幅を行うことができるファイバ増幅器が少なくとも 1段設けられてい る場合には、 前記ファイバ増幅器は、 希土類元素が添加されたフォスフェイ卜 ガラス及び酸化ビスマス系ガラスのいずれかを主材とする光ファイバを光導波 路部材として有することとすることができる。  In this case, when at least one stage of fiber amplifier capable of performing optical amplification is provided in a part of each optical path including the optical fiber, the fiber amplifier is a rare earth element. An optical fiber mainly composed of either a phosphate glass to which an element is added or a bismuth oxide-based glass can be provided as an optical waveguide member.
本発明は、 第 2の観点からすると、 単一波長の光を発生する光源装置であつ て、 単一波長の光を発生する光源と、 該光源からの光を所定周波数のパルス光 に変換して出力する光変調器とを有する光発生部と;前記光発生部によって発 生されたパルス光を増幅する少なくとも 1段のファイバ増幅器を含む光増幅部 と;前記光変調器から出力される前記パルス光の周波数を制御することにより 前記ファイバ増幅器からの出力光の光量を制御する光量制御装置と;を備える 第 2の光源装置である。  According to a second aspect of the present invention, there is provided a light source device for generating light of a single wavelength, a light source for generating light of a single wavelength, and converting light from the light source into pulse light of a predetermined frequency. An optical modulator having an optical modulator for outputting the optical signal; an optical amplifier including at least one fiber amplifier for amplifying the pulse light generated by the optical generator; and an optical amplifier output from the optical modulator. A light amount control device that controls the light amount of the output light from the fiber amplifier by controlling the frequency of the pulse light.
これによれば、 光発生部内では、 光源から単一波長の光が発生され、 その光 が光変調器によって所定周波数のパルス光に変換され出力される。 そして、 こ のパルス光は、 光増幅部によって増幅されピークパワーのより大きなパルス光 として出力される。 しかるに、 パルス光の単位時間当たりの光量 (積算光量) は、 パルス光のピークパワーがほぼ一定であれば、 その周波数に応じて増減す るので、 光量制御装置が光変調器から出力されるパルス光の周波数を制御する ことにより、 ファイバ増幅器からの出力光の光量を設定光量 (目標光量) に一 致させることができる。 本発明によるパルス光の周波数 (単位時間当たりのパ ルス数) 制御による光量調整では、 前述した請求項 1に記載の発明に比べて、 よリ高速にかつより細やかな光量調整を行うことが可能となリ、 設定光量が所 定範囲内にあれば如何なる値に設定されても光量をほぼ一致させることができ る。 また、 光出力と制御量とのリニアリティも第 1の光源装置と同等以上にな る。 According to this, in the light generator, light of a single wavelength is generated from the light source, and the light is converted into pulse light of a predetermined frequency by the optical modulator and output. The pulse light is amplified by the optical amplifier and output as a pulse light having a higher peak power. However, if the peak power of the pulsed light is almost constant, the light amount per unit time (integrated light amount) increases or decreases according to the frequency. By controlling the frequency of the light, the light intensity of the output light from the fiber amplifier can be made to match the set light intensity (target light intensity). In the light amount adjustment by controlling the frequency (the number of pulses per unit time) of the pulse light according to the present invention, it is possible to perform the light amount adjustment at higher speed and more finely as compared with the invention according to claim 1 described above. Tori, set light intensity The light quantity can be made to substantially match no matter what value is set within the fixed range. Also, the linearity between the light output and the control amount is equal to or greater than that of the first light source device.
この場合において、 前記光増幅部に入力するパルス光の周波数に応じた前記 光増幅部の出力強度マップが記憶された記憶装置を更に備える場合には、 前記 光量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前記光変 調器から出力される前記パルス光の周波数を制御することとしても良い。 光変 調器からのパルス光の周波数に応じて光増幅器の入力光の強度が変化し、 光増 幅部を構成するファイバ増幅器の利得は入力光強度依存性を有するが、 本発明 によれば、 前記入力光強度依存性に起因する光増幅部からの出力パルスのピー クパワー変化の影響を受けることのない、 高精度な光量制御が可能となる。 本発明の第 2の光源装置では、 前記光量制御装置は、 前記光変調器から出力 される前記パルス光のピークパワーを更に制御することとしても良い。 かかる 場合には、 パルス光のピークパワーに変動があるような場合であっても、 精度 の良い光量制御が可能となる。  In this case, when the storage device further includes a storage device that stores an output intensity map of the optical amplification unit according to a frequency of the pulse light input to the optical amplification unit, the light intensity control device includes: The frequency of the pulse light output from the optical modulator may be controlled based on a predetermined light amount. Although the intensity of the input light of the optical amplifier changes according to the frequency of the pulse light from the optical modulator, the gain of the fiber amplifier constituting the optical amplifier has input light intensity dependence. In addition, high-precision light quantity control can be performed without being affected by a change in the peak power of the output pulse from the optical amplifier due to the input light intensity dependency. In the second light source device of the present invention, the light amount control device may further control the peak power of the pulse light output from the optical modulator. In such a case, even if the peak power of the pulsed light fluctuates, accurate light amount control can be performed.
本発明の第 2の光源装置では、 前記光変調器が、 電気光学変調器である場合 に、 前記光量制御装置は、 前記光変調器に印加する電圧パルスの周波数を制御 することにより、 前記パルス光の周波数を制御することとしても良い。 電気光 学変調器の出力パルス光の周波数は、 その光変調器に印加する電圧パルスの周 波数に一致する。  In the second light source device of the present invention, when the optical modulator is an electro-optic modulator, the light amount control device controls the frequency of a voltage pulse applied to the optical modulator, thereby controlling the pulse. The frequency of light may be controlled. The frequency of the output pulse light of the electro-optical modulator matches the frequency of the voltage pulse applied to the optical modulator.
本発明の第 2の光源装置では、 前記光増幅部は複数並列に設けられ、 前記各 光増幅部の光出力端部は光ファイバによりそれぞれ構成されていても良い。 この場合において、 前記複数の光増幅部をそれぞれ構成する前記複数の光フ アイバは、 束ねられてバンドル—ファイバが構成されていても良い。 通常、 光 ファイバの径は細いので、 1 0 0本以上束ねても直径が数 m m程度以内に収め ることができ、 そのバンドル一ファイバの出力段に何らかの光学素子を配置す る場合に、 小型の光学素子を配置できる。 In the second light source device of the present invention, a plurality of the optical amplifiers may be provided in parallel, and an optical output end of each of the optical amplifiers may be configured by an optical fiber. In this case, the plurality of optical fibers constituting the plurality of optical amplifiers may be bundled to form a bundle-fiber. In general, the diameter of an optical fiber is small, so that even if 100 or more fibers are bundled, the diameter can be kept within about several mm, and some kind of optical element is arranged in the output stage of one fiber of the bundle. In this case, a small optical element can be arranged.
本発明の第 2の光源装置では、 前記光増幅部から出力される光の波長を変換 する波長変換部を更に備えていても良い。 かかる場合には、 波長変換部からの 出力光の光量は、 光増幅部出力、 ひいては光変調器からのパルス光の入力強度 (光量) に応じた値となる。 但し、 確実にパルス光の入力強度 (光量) に比例 した値となるわけではなく、 光増幅部の出力パルスのピーク強度に対し、 最高 で波長変換部から出力される高調波の次数のべき乗に比例した非線形の依存性 を示す。 一方、 前記光変調器が電気光学変調器である場合には、 その出力光の パルスピーク強度の、 電気光学変調器に印加される電圧パルスのパルスピーク 強度依存性は、 c o s ( V ) であるため、 上記の波長変換部の非線形な依存性 は緩和される。 従って、 波長変換部を備える場合には、 前記光変調器は、 電気 光学変調器であることが望ましい。  The second light source device of the present invention may further include a wavelength converter for converting a wavelength of light output from the optical amplifier. In such a case, the light amount of the output light from the wavelength conversion unit becomes a value corresponding to the output intensity (light amount) of the pulse light from the optical amplifying unit and eventually from the optical modulator. However, the value is not necessarily proportional to the input intensity (light intensity) of the pulsed light. The peak intensity of the output pulse of the optical amplifier is at most a power of the order of the harmonic output from the wavelength converter. It shows a proportional non-linear dependence. On the other hand, when the optical modulator is an electro-optical modulator, the dependence of the pulse peak intensity of the output light on the pulse peak intensity of the voltage pulse applied to the electro-optical modulator is cos (V). Therefore, the above-described nonlinear dependence of the wavelength conversion unit is reduced. Therefore, when a wavelength converter is provided, it is preferable that the optical modulator is an electro-optical modulator.
この場合において、 前記光発生部は、 赤外域から可視域までの範囲内の単一 波長のレーザ光を発生し、 前記波長変換部は、 前記レーザ光の高調波である紫 外光を出力することとしても良い。 例えば、 前記光発生部は、 波長 1 . 5 t m 付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 m 付近の前記レーザ光の 8倍高調波及び 1 0倍高調波のいずれかを発生すること とすることができる。  In this case, the light generation unit generates a single-wavelength laser light within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser light. It is good. For example, the light generating section generates a single-wavelength laser light having a wavelength of about 1.5 tm, and the wavelength converting section generates an eighth harmonic of the laser light having a wavelength of about 1.5 m and 10 times higher. Any of the harmonics can be generated.
本発明は、 第 3の観点からすると、 単一波長の光を発生する光源装置であつ て、 単一波長の光を発生する光源と、 該光源からの光を所定周波数のパルス光 に変換して出力する光変調器とを有する光発生部と;前記光発生部によって発 生されたパルス光を増幅する少なくとも 1段のファイバ増幅器を含む光増幅部 と;前記光変調器から出力される前記パルス光のピークパワーを制御すること により前記光増幅部からの出力光の光量を制御する光量制御装置と;を備える 第 3の光源装置である。  According to a third aspect of the present invention, there is provided a light source device for generating light of a single wavelength, a light source for generating light of a single wavelength, and converting light from the light source into pulse light of a predetermined frequency. An optical modulator having an optical modulator for outputting the optical signal; an optical amplifier including at least one fiber amplifier for amplifying the pulse light generated by the optical generator; and an optical amplifier output from the optical modulator. A light amount control device that controls the light amount of the output light from the optical amplifier by controlling the peak power of the pulse light.
これによれば、 光発生部内では、 光源から単一波長の光が発生され、 その光 が光変調器によって所定周波数のパルス光に変換され出力される。 そして、 こ のパルス光は、 光増幅部によって増幅されピークパワーのより大きなパルス光 として出力される。 光増幅部から出力されるパルス光の単位時間当たりの光量 (積算光量) は、 当然に光変調器からのパルス光のピークパワーに応じて増減 するので、 光量制御装置が光変調器から出力されるパルス光のピークパワーを 制御することにより、 ファイバ増幅器からの出力光の光量を設定光量 (目標光 量) に一致させることができる。 本発明によるパルス光のピークパワー制御に よる光量調整では、 前述した第 1の光源装置に比べて、 より高速にかつより細 やかな光量調整を行うことが可能となり、 設定光量が所定範囲内にあれば如何 なる値に設定されても光量をほぼ一致させることができる。 According to this, in the light generation section, light of a single wavelength is generated from the light source, and the light is emitted. Is converted into pulsed light of a predetermined frequency by the optical modulator and output. The pulse light is amplified by the optical amplifier and output as a pulse light having a higher peak power. The amount of light (integrated light) per unit time of the pulse light output from the optical amplifier naturally increases or decreases according to the peak power of the pulse light from the optical modulator. Therefore, the light amount control device is output from the optical modulator. By controlling the peak power of the pulsed light, the light quantity of the output light from the fiber amplifier can be made to match the set light quantity (target light quantity). In the light amount adjustment by the peak power control of the pulse light according to the present invention, the light amount can be adjusted more quickly and more finely than in the first light source device described above, and the set light amount is within a predetermined range. If there is any value, the light quantity can be made to substantially match.
この場合において、 前記光増幅部に入力するパルス光の強度に応じた前記光 増幅部の出力強度マップが記憶された記憶装置を更に備える場合には、 前記光 量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前記光変調 器から出力される前記パルス光のピークパワーを制御することとしても良い。 かかる場合には、 光増幅部を構成するファイバ増幅器の利得の入力光強度依存 性に起因する光増幅部からの出力パルスのピークパワー変化の影響を受けるこ とのない、 高精度な光量制御が可能となる。  In this case, in the case where the apparatus further includes a storage device storing an output intensity map of the optical amplification unit according to the intensity of the pulsed light input to the optical amplification unit, the light intensity control device includes the output intensity map. The peak power of the pulse light output from the optical modulator may be controlled based on the predetermined light amount. In such a case, high-precision light quantity control is performed without being affected by the change in the peak power of the output pulse from the optical amplifier due to the input light intensity dependence of the gain of the fiber amplifier constituting the optical amplifier. It becomes possible.
本発明の第 3の光源装置では、 前記光変調器は、 電気光学変調器であり、 前 記光量制御装置は、 前記光変調器に印加する電圧パルスのピークレベルを制御 することにより、 前記パルス光のピークパワーを制御することとしても良い。 電気光学変調器からの出力光のパルスピーク強度は電気光学変調器に印加され る電圧パルスのパルスピーク強度に依存する。  In the third light source device of the present invention, the optical modulator is an electro-optic modulator, and the light amount control device controls the peak level of a voltage pulse applied to the optical modulator, thereby controlling the pulse level. The peak power of light may be controlled. The pulse peak intensity of the output light from the electro-optic modulator depends on the pulse peak intensity of the voltage pulse applied to the electro-optic modulator.
本発明の第 3の光源装置では、 前記光増幅部は複数並列に設けられ、 前記各 光増幅部の光出力端部は光ファイバによりそれぞれ構成されていても良い。 こ の場合において、 前記複数の光増幅部をそれぞれ構成する前記複数の光フアイ バは、 束ねられてバンドル一ファイバが構成されていても良い。 通常、 光ファ ィバの径は細いので、 1 0 0本以上束ねても直径が数 m m程度以内に収めるこ とができ、 そのバンドル一ファイバの出力段に何らかの光学素子を配置する場 合に、 小型の光学素子を配置できる。 In the third light source device of the present invention, a plurality of the optical amplifiers may be provided in parallel, and an optical output end of each of the optical amplifiers may be constituted by an optical fiber. In this case, the plurality of optical fibers constituting each of the plurality of optical amplifiers may be bundled to form a bundle of fibers. Usually, the optical fiber Since the diameter of the fiber is small, it can be kept within a few millimeters even if 100 or more fibers are bundled. Elements can be arranged.
本発明の第 3の光源装置では、 前記光増幅部は複数並列に設けられ、 前記各 光増幅部の光出力端部は光ファイバによりそれぞれ構成されている場合に、 前 記複数の光増幅部のそれぞれからの光出力を個別に遅延させて、 前記光出力を 時間的にずらして行わせる遅延部を更に備えていても良い。 かかる場合には、 各光ファイバから出力される光が時間的に重なることがなくなるので、 結果的 に空間的コヒーレンシ一を低減することが可能になる。  In the third light source device of the present invention, the plurality of optical amplifiers are provided in parallel, and the optical output terminals of the respective optical amplifiers are each configured by an optical fiber. A delay unit may be further provided for individually delaying the optical output from each of the above, and performing the optical output in a time-shifted manner. In such a case, the lights output from the respective optical fibers do not overlap in time, and as a result, the spatial coherency can be reduced.
本発明の第 3の光源装置では、 前記光増幅部から出力される光の波長を変換 する波長変換部を更に備えていても良い。 かかる場合には、 波長変換部からの 出力光の光量は、 光増幅部出力、 ひいては光変調器からのパルス光の入力強度 The third light source device of the present invention may further include a wavelength conversion unit that converts a wavelength of light output from the optical amplification unit. In such a case, the light quantity of the output light from the wavelength conversion unit is determined by the output of the optical amplification unit, and thus the input intensity of the pulse light from the optical modulator
(光量) に応じた値となる。 但し、 確実にパルス光の入力強度 (光量) に比例 した値となるわけではなく、 光増幅部の出力パルスのピーク強度に対し、 最高 で波長変換部から出力される高調波の次数のべき乗に比例した非線形の依存性 を示す。 一方、 前記光変調器が電気光学変調器である場合には、 その出力光の パルスピーク強度の、 電気光学変調器に印加される電圧パルスのパルスピーク 強度依存性は、 c o s ( V ) であるため、 上記の波長変換部の非線形な依存性 は緩和される。 従って、 波長変換部を備える場合には、 前記光変調器は、 電気 光学変調器であることが望ましい。 (Light amount). However, the value is not necessarily proportional to the input intensity (light intensity) of the pulsed light. The peak intensity of the output pulse of the optical amplifier is at most a power of the order of the harmonic output from the wavelength converter. It shows a proportional non-linear dependence. On the other hand, when the optical modulator is an electro-optical modulator, the dependence of the pulse peak intensity of the output light on the pulse peak intensity of the voltage pulse applied to the electro-optical modulator is cos (V). Therefore, the above-described nonlinear dependence of the wavelength conversion unit is reduced. Therefore, when a wavelength converter is provided, it is preferable that the optical modulator is an electro-optical modulator.
この場合において、 前記光発生部は、 赤外域から可視域までの範囲内の単一 波長のレーザ光を発生し、 前記波長変換部は、 前記レーザ光の高調波である紫 外光を出力することとしても良い。 例えば、 前記光発生部は、 波長 1 . 5 /_t m 付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 m付近の前記レーザ光の 8倍高調波及び 1 0倍高調波のいずれかを発生するこ ととすることができる。 本発明の第第 2、 第 3の光源装置では、 前記光発生部が、 前記光源としてレ 一ザ光を発振するレーザ光源を有する場合に、 前記レーザ光の中心波長を所定 の設定波長に維持するための波長安定化に関連する前記レーザ光の光学特性を モニタするビームモニタ機構と;前記ビームモニタ機構の検出基準波長の温度 依存性のデータに基づいて、 波長キヤリブレーションを行う波長キヤリブレー シヨン制御装置と;を更に備えることとすることができる。 かかる場合には、 波長キャリブレーション制御装置により、 ビームモニタ機構の検出基準波長の 温度依存性のデータに基づいて、 波長キャリブレーションが行われるので、 ビ ー厶モニタ機構の検出基準波長を設定波長に正確に設定することができ、 これ によりビームモニタ機構の雰囲気の温度等が変動しても、 それに影響を受ける ことなく、 ビームモニタ機構を用いてレーザ光の中心波長を所定の設定波長に 確実に維持するような波長安定化制御が可能になる。 In this case, the light generation unit generates a laser beam of a single wavelength within a range from an infrared region to a visible region, and the wavelength conversion unit outputs ultraviolet light that is a harmonic of the laser beam. It is good. For example, the light generation unit generates a single-wavelength laser light having a wavelength of around 1.5 / _t m, and the wavelength conversion unit generates an 8th harmonic of the laser light having a wavelength of around 1.5 m and Either of the tenth harmonic can be generated. In the second and third light source devices of the present invention, when the light generation unit has a laser light source that oscillates laser light as the light source, the center wavelength of the laser light is maintained at a predetermined set wavelength. Beam monitoring mechanism for monitoring the optical characteristics of the laser light related to wavelength stabilization for performing wavelength calibration; and wavelength calibration for performing wavelength calibration based on data on the temperature dependence of the detection reference wavelength of the beam monitoring mechanism. And a control device. In such a case, since the wavelength calibration is performed by the wavelength calibration control device based on the temperature dependence data of the detection reference wavelength of the beam monitor mechanism, the detection reference wavelength of the beam monitor mechanism is set to the set wavelength. It is possible to accurately set the center wavelength of the laser beam to a predetermined set wavelength using the beam monitor mechanism without being affected even if the temperature or the like of the atmosphere of the beam monitor mechanism fluctuates. Wavelength stabilization control that can be maintained becomes possible.
この場合において、 前記光増幅部が、 複数並列に設けられている場合には、 前記複数の光増幅部を構成する前記複数の光ファイバを介した同一波長の複数 の光束の偏光状態を揃える偏光調整装置と;前記複数の光ファイバを介した全 ての光束を同一の偏光方向を有する複数の直線偏光光束に変換する偏光方向変 換装置と;を更に備えることとすることができる。  In this case, when the plurality of optical amplifying units are provided in parallel, the polarization for aligning the polarization states of a plurality of light beams of the same wavelength through the plurality of optical fibers constituting the plurality of optical amplifying units. The apparatus may further include an adjustment device; and a polarization direction conversion device that converts all light beams passing through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
この場合において、 前記ファイバ増幅器は、 希土類元素が添加されたフォス フェイ卜ガラス及び酸化ビスマス系ガラスのいずれかを主材とする光ファイバ を光導波路部材として有することとすることができる。  In this case, the fiber amplifier may include, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
本発明は、 第 4の観点からすると、 レーザ光を発振するレーザ光源と;前記 レーザ光の中心波長を所定の設定波長に維持するための波長安定化に関連する 前記レーザ光の光学特性をモニタするビームモニタ機構と;前記ビームモニタ 機構の検出基準波長の温度依存性のデータに基づいて、 波長キヤリブレーショ ンを行う第 1の制御装置と;を備える第 4の光源装置である。  According to a fourth aspect of the present invention, there is provided a laser light source that oscillates laser light; and monitors an optical characteristic of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength. A fourth light source device, comprising: a beam monitor mechanism for performing a wavelength calibration based on data on the temperature dependence of a detection reference wavelength of the beam monitor mechanism.
これによれば、 第 1の制御装置により、 ビームモニタ機構の検出基準波長の 温度依存性のデータに基づいて、 波長キャリブレーションが行われる。 このた め、ビームモニタ機構の検出基準波長を設定波長に正確に設定することができ、 これによりビームモニタ機構の雰囲気の温度等が変動しても、 それに影響を受 けることなく、 ビームモニタ機構を用いてレーザ光の中心波長を所定の設定波 長に確実に維持するような波長安定化制御が可能になる。 According to this, the first control device sets the detection reference wavelength of the beam monitor mechanism. Wavelength calibration is performed based on the temperature dependence data. For this reason, the detection reference wavelength of the beam monitor mechanism can be accurately set to the set wavelength, so that even if the temperature or the like of the atmosphere of the beam monitor mechanism fluctuates, the beam monitor mechanism is not affected. The wavelength stabilization control that ensures that the center wavelength of the laser light is maintained at a predetermined set wavelength can be performed by using.
この場合において、 前記設定波長に近い絶対波長を提供する絶対波長提供源 を更に備えている場合には、 前記第 1の制御装置は、 前記絶対波長提供源から 提供される絶対波長に対して前記ビームモニタ機構の検出基準波長をほぼ一致 させる絶対波長キャリブレーションを行うとともに、 前記温度依存性のデータ に基づいて前記検出基準波長を前記設定波長に一致させる設定波長キヤリプレ —シヨンを行うこととすることができる。 かかる場合には、 第 1の制御装置に より、 絶対波長提供源から提供される絶対波長に対してビームモニタ機構の検 出基準波長をほぼ一致させる絶対波長キャリブレーションが行なわれるととも に、 前記温度依存性データに基づいて前記検出基準波長を前記設定波長に一致 させる設定波長キャリブレーションが行なわれる。 すなわち、 既知のビー厶モ ニタ機構の検出基準波長の温度依存性のデータを用いて、 絶対波長キヤリブレ ーシヨン後のビームモニタ機構の検出基準波長を設定波長に一致させる設定波 長キャリブレーションが行われる。 このため、 常に確実にビームモニタ機構の 検出基準波長を設定波長に正確に設定することができ、 これにより、 ビー厶モ 二夕機構の雰囲気の温度等が変動しても、 それに影響を受けることなく、 ビー 厶モニタ機構を用いてレーザ光の中心波長を所定の設定波長に確実に維持する ような波長安定化制御が可能になる。  In this case, if the apparatus further comprises an absolute wavelength providing source that provides an absolute wavelength close to the set wavelength, the first control device may determine the absolute wavelength provided from the absolute wavelength providing source. Absolute wavelength calibration is performed so that the detection reference wavelength of the beam monitor mechanism substantially matches, and a setting wavelength calibration that matches the detection reference wavelength with the setting wavelength is performed based on the temperature dependency data. Can be. In such a case, the first control device performs absolute wavelength calibration for making the detection reference wavelength of the beam monitor mechanism substantially coincide with the absolute wavelength provided from the absolute wavelength providing source. Based on the temperature dependency data, a set wavelength calibration for matching the detection reference wavelength to the set wavelength is performed. That is, using the known temperature dependence data of the detection reference wavelength of the beam monitor mechanism, the set wavelength calibration is performed to match the detection reference wavelength of the beam monitor mechanism after the absolute wavelength calibration to the set wavelength. . For this reason, the detection reference wavelength of the beam monitor mechanism can always be accurately set to the set wavelength, and therefore, even if the temperature of the atmosphere of the beam monitor mechanism fluctuates, it is affected by the fluctuation. Instead, it is possible to perform wavelength stabilization control by using a beam monitor mechanism to reliably maintain the center wavelength of the laser beam at a predetermined set wavelength.
なお、本明細書において、 「設定波長に近い絶対波長」は、設定波長と同一の 波長をも含む概念である。  In the present specification, “absolute wavelength close to the set wavelength” is a concept that includes the same wavelength as the set wavelength.
この場合において、 前記ビームモニタ機構は、 フアブリペロー■ェタロンを 含み、 前記温度依存性のデータは、 前記フアブリペロー ·ェタロンの共鳴波長 の温度依存性の測定結果に基づくデータを含む場合には、 前記第 1の制御装置 は、 前記ビームモニタ機構を構成する前記フアプリペロー ·エタロンの温度を 制御することにより、 前記検出基準波長の前記絶対波長キャリブレーション及 び前記設定波長キヤリプレーションを行うこととしても良い。かかる場合には、 フアブリペロー ·エタロンの波長検出の基準となる共鳴波長の温度依存性を利 用して、 その検出基準波長を設定波長に設定することが可能となる。 In this case, the beam monitoring mechanism includes a Fabry-Perot etalon, and the temperature-dependent data includes a resonance wavelength of the Fabry-Perot etalon. When the first control device includes data based on the measurement result of the temperature dependence of the absolute value of the detection reference wavelength, The wavelength calibration and the set wavelength calibration may be performed. In such a case, it is possible to set the detection reference wavelength to the set wavelength by using the temperature dependence of the resonance wavelength, which is the reference for the wavelength detection of Fabry-Perot etalon.
本発明の第 4の露光装置では、 前記温度依存性のデータは、 前記レーザ光源 から発振される前記レーザ光の中心波長の温度依存性のデータを更に含み、 前記第 1の制御装置は、 前記絶対波長キャリブレーションを行うに際に、 前 記レーザ光源の波長制御をも併せて行うこととしても良い。 かかる場合には、 前述した絶対波長キヤリブレーションを、 レーザ光の波長制御を行わない場合 に比べて短時間で完了することができる。 但し、 絶対波長キャリブレーション を行う際に、 レーザ光の波長制御を必ずしも行う必要はない。  In the fourth exposure apparatus of the present invention, the temperature dependency data further includes temperature dependency data of a center wavelength of the laser light oscillated from the laser light source, and the first control device includes: When performing the absolute wavelength calibration, the wavelength control of the laser light source may be performed together. In such a case, the above-described absolute wavelength calibration can be completed in a shorter time than when the wavelength control of the laser beam is not performed. However, it is not always necessary to control the wavelength of laser light when performing absolute wavelength calibration.
本発明の第 4の光源装置では、 前記レーザ光源からのレーザ光を増幅するフ アイバ増幅器を更に備えていても良い。 かかる場合には、 ファイバ増幅器によ りレーザ光源からのレーザ光を増幅することができるので、 要求される光量が 大きい場合であっても、 小型のレーザ光源、 例えば、 D F B半導体レーザ、 フ アイバーレーザ等の固体レーザを用いることが可能となり、 装置の小型 ·軽量 化が可能となる。  The fourth light source device of the present invention may further include a fiber amplifier for amplifying the laser light from the laser light source. In such a case, the laser light from the laser light source can be amplified by the fiber amplifier. Therefore, even when the required light amount is large, a small laser light source such as a DFB semiconductor laser or a fiber laser can be used. It is possible to use a solid-state laser such as that described above, and it is possible to reduce the size and weight of the device.
本発明の第 4の光源装置では、 レーザ光源からのレーザ光を増幅するフアイ バ増幅器を備えている場合に、 前記増幅されたレーザ光の波長を変換する非線 形光学結晶を含む波長変換器を更に備えていても良い。 かかる場合には、 波長 変換器により増幅されたレーザ光の波長変換が可能となるので、 例えば、 波長 変換器によりレーザ光の波長変換を行って高調波を発生させることにより、 短 波長の高いエネルギビームを出力する小型の光源装置を得ることが可能になる。 本発明の第 4の光源装置では、 前記絶対波長提供源は、 前記レーザ光が入射 する吸収セルであり、 前記第 1の制御装置は、 前記絶対波長キヤリプレーショ ンを行う際に、 前記吸収セルの前記設定波長に最も近い吸収線の吸収が最大と なり、 かつ前記フアブリペロー■エタロンの透過率が最大となるようにするこ ととしても良い。 In a fourth light source device of the present invention, when a fiber amplifier for amplifying laser light from a laser light source is provided, a wavelength converter including a non-linear optical crystal for converting the wavelength of the amplified laser light May be further provided. In such a case, the wavelength conversion of the laser light amplified by the wavelength converter becomes possible. For example, by converting the wavelength of the laser light by the wavelength converter to generate a harmonic, a short-wavelength high energy It is possible to obtain a small light source device that outputs a beam. In the fourth light source device of the present invention, the absolute wavelength providing source receives the laser light. The first control device, when performing the absolute wavelength calibration, maximizes absorption of an absorption line closest to the set wavelength of the absorption cell, and the Fabry-Perot etalon The maximum transmittance may be set to be maximum.
ここで、 「設定波長に最も近い吸収線」には、 「設定波長と同一波長の吸収線」 も含まれる。  Here, “the absorption line closest to the set wavelength” includes “the absorption line having the same wavelength as the set wavelength”.
本発明の第 4の光源装置では、前記設定波長キャリブレーションの終了後に、 前記設定波長キヤリブレーションが終了した前記ビームモニタ機構のモニタ結 果に基づいて、 前記レーザ光源からの前記レーザ光の波長をフィードバック制 御する第 2の制御装置を更に備えることとすることができる。かかる場合には、 第 2の制御装置により、 その検出基準波長が設定波長に正確に設定されたビー 厶モニタ機構のモニタ結果に基づいて、 レーザ光源からのレーザ光の波長が制 御されるので、 そのレーザ光の波長を設定波長に安定的に維持することができ る。  In the fourth light source device of the present invention, after the completion of the setting wavelength calibration, the wavelength of the laser light from the laser light source is determined based on a monitoring result of the beam monitoring mechanism after the completion of the setting wavelength calibration. And a second control device that performs feedback control of the control. In such a case, the wavelength of the laser beam from the laser light source is controlled by the second control device based on the monitoring result of the beam monitor mechanism in which the detection reference wavelength is accurately set to the set wavelength. However, the wavelength of the laser beam can be stably maintained at the set wavelength.
本発明の第 4の光源装置では、 前記レーザ光源の出力段に並列に配置され、 ファイバ増幅器をそれぞれ含む複数の光増幅部と;前記複数の光増幅部をそれ ぞれ構成する前記複数の光ファイバを介した同一波長の複数の光束の偏光状態 を揃える偏光調整装置と;前記複数の光ファイバを介した全ての光束を同一の 偏光方向を有する複数の直線偏光光束に変換する偏光方向変換装置と;を更に 備えることとすることができる。  In a fourth light source device according to the present invention, a plurality of optical amplifiers each including a fiber amplifier and arranged in parallel at an output stage of the laser light source; and the plurality of optical amplifiers respectively configuring the plurality of optical amplifiers. A polarization adjusting device for aligning the polarization states of a plurality of light beams of the same wavelength through a fiber; and a polarization direction conversion device for converting all the light beams through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction. And;
この場合において、 前記ファイバ増幅器は、 希土類元素が添加されたフォス フェイ卜ガラス及び酸化ビスマス系ガラスのいずれかを主材とする光ファイバ を光導波路部材として有することとすることができる。  In this case, the fiber amplifier may include, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
本発明は、 第 5の観点からすると、 複数の光ファイバと;前記複数の光ファ ィバを介した同一波長の複数の光束の偏光状態を揃える偏光調整装置と;前記 複数の光ファイバを介した全ての光束を同一の偏光方向を有する複数の直線偏 光光束に変換する偏光方向変換装置とを備える第 5の光源装置である。 According to a fifth aspect of the present invention, there are provided: a plurality of optical fibers; a polarization adjusting device for aligning a polarization state of a plurality of light beams having the same wavelength via the plurality of optical fibers; All the luminous fluxes into a plurality of linearly polarized light beams having the same polarization direction. A fifth light source device comprising: a polarization direction conversion device that converts the light into a light beam.
これによれば、 偏光調整装置が複数の光ファイバから射出される複数の光束 の偏光状態を揃えた後、 偏光方向変換装置が、 複数の光ファイバを介した全て の光束を同一の偏光方向を有する複数の直線偏光光束に変換するので、 簡易な 構成で、 同一の偏光方向を有する複数の直線偏光光束を得ることができる。 本発明の第 5の光源装置では、 前記偏光調整装置が、 前記各光ファイバを介 した複数の光束それぞれの偏光状態をほぼ円偏光とする場合には、 前記偏光方 向変換装置が四分の一波長板を有する構成とすることができる。 かかる場合に は、 偏光調整装置によって各光ファイバを介した複数の光束それぞれがほぼ円 偏光となっているので、 複数の光束の全てを、 偏光方向変換装置が有する四分 の一波長板を介させることにより、 同一の偏光方向を有する複数の直線偏光光 束に変換することができる。 従って、 偏光方向変換装置を、 1枚の四分の一波 長板という非常に簡単な構成としつつ、 複数の光束を、 同一の偏光方向を有す る複数の直線偏光光束に変換することができる。なお、直線偏光の偏光方向は、 四分の一波長板を形成する結晶材料等の光学軸の方向によって決定される。 こ のため、 四分の一波長板を形成する結晶材料等の光学軸の方向を調整すること により、 任意の同一直線偏光方向を有する複数の光束を得ることができる。 ここで、 前記光ファイバがほぼ円筒対称の構造を有する場合には、 前記偏光 調整装置が、 前記各光ファイバに入射する複数の光束それぞれの偏光状態をほ ぼ円偏光とする構成とすることができる。 これは、 円筒対称の構造を有する光 ファイバに円偏光を入射した場合には、 その光ファイバからは円偏光が射出さ れるからである。 なお、 光ファイバを完全に円筒対称の構造とすることは不可 能なので、 光ファイバの長さは短い方が好ましい。  According to this, after the polarization adjusting device aligns the polarization states of the plurality of light beams emitted from the plurality of optical fibers, the polarization direction conversion device converts all the light beams passing through the plurality of optical fibers into the same polarization direction. Since the light beam is converted into a plurality of linearly polarized light beams, a plurality of linearly polarized light beams having the same polarization direction can be obtained with a simple configuration. In the fifth light source device of the present invention, when the polarization adjusting device sets the polarization state of each of the plurality of light beams passing through each of the optical fibers to substantially circular polarization, the polarization direction conversion device is configured to be a quarter. A configuration having a single wavelength plate can be employed. In such a case, since the plurality of light beams passing through each optical fiber are substantially circularly polarized by the polarization adjusting device, all of the plurality of light beams are transmitted through the quarter-wave plate of the polarization direction conversion device. By doing so, it can be converted into a plurality of linearly polarized light beams having the same polarization direction. Therefore, it is possible to convert a plurality of light beams into a plurality of linearly polarized light beams having the same polarization direction while having a very simple configuration of the polarization direction conversion device as one quarter-wavelength plate. it can. The polarization direction of the linearly polarized light is determined by the direction of the optical axis of the crystal material or the like forming the quarter-wave plate. Therefore, by adjusting the direction of the optical axis of the crystal material or the like forming the quarter-wave plate, it is possible to obtain a plurality of luminous fluxes having any given linear polarization direction. Here, when the optical fiber has a substantially cylindrically symmetric structure, the polarization adjusting device may be configured to set the polarization state of each of the plurality of light beams incident on each of the optical fibers to substantially circular polarization. it can. This is because when circularly polarized light is incident on an optical fiber having a cylindrically symmetric structure, circularly polarized light is emitted from the optical fiber. Since it is impossible to make the optical fiber completely cylindrically symmetric, it is preferable that the length of the optical fiber is short.
本発明の第 5の光源装置では、 前記偏光調整装置が前記各光ファイバを介し た複数の光束それぞれが全てほぼ同一の偏光状態で、 任意の楕円偏光とする場 合には、 前記偏光方向変換装置が、 偏波面を回転する二分の一波長板と、 前記 二分の一波長板と光学的に直列接続された四分の一波長板とを有する構成とす ることができる。 ここで、 二分の一波長板と四分の一波長板との直列接続にあ たっては、 どちらを光路における上流側に配置してもよい。 例えば、 二分の一 波長板を上流側に配置した場合には、 共通の二分の一波長板を介することによ り、 各光ファイバを介した複数の光束の偏波面が同様に回転された後、 更に共 通の四分の一波長板を介することにより、 全ての光束が同一偏光方向を有する 直線偏光となる。 また、 四分の一波長板を上流側に配置した場合にも、 二分の 一波長板を上流側に配置した場合と同様に、 全ての光束を、 同一偏光方向を有 する直線偏光とすることができる。 したがって、 偏光方向変換装置を、 1枚の 二分の一波長板と 1枚の四分の一波長板という簡易な構成とすることができる c この場合には、 二分の一波長板及び四分の一波長板を形成する結晶材料等の光 学軸の方向を調整することにより、 任意の同一直線偏光方向を有する複数の光 束を得ることができる。 In the fifth light source device of the present invention, in the case where the polarization adjusting device is configured such that each of the plurality of light beams passing through each of the optical fibers is substantially in the same polarization state and has any elliptically polarized light, the polarization direction conversion may be performed. A half-wave plate rotating the plane of polarization; A configuration having a half-wave plate and a quarter-wave plate optically connected in series can be employed. Here, when the half-wave plate and the quarter-wave plate are connected in series, either of them may be arranged on the upstream side in the optical path. For example, when a half-wave plate is arranged on the upstream side, the polarization plane of a plurality of light beams passing through each optical fiber is similarly rotated by passing through a common half-wave plate. By passing through a common quarter-wave plate, all the light beams become linearly polarized light having the same polarization direction. Also, when the quarter-wave plate is arranged on the upstream side, as in the case where the half-wave plate is arranged on the upstream side, all light beams should be linearly polarized light having the same polarization direction. Can be. Therefore, the polarization direction changing device can have a simple configuration of one half-wave plate and one quarter-wave plate.c In this case, the half-wave plate and the quarter-wave plate By adjusting the direction of the optical axis of a crystal material or the like forming a single-wavelength plate, it is possible to obtain a plurality of luminous fluxes having arbitrary identical linear polarization directions.
また、 本発明の第 5の光源装置では、 前記複数の光ファイバそれぞれが、 前 記複数の光ファイバに入射する複数の光束それぞれを増幅対象光とする光ファ ィバ増幅器を構成する、 前記増幅対象光が導波される光ファイバである構成と することができる。 かかる場合には、 各光ファイバが入射した光がそれぞれ増 幅されて各光ファイバから射出されるので、 偏光方向変換装置からの射出光と して、 それぞれが高強度であり、 かつ同一の偏光方向を有する複数の直線偏光 光束を得ることができる。 この結果、 光源装置としての射出光光量の増大を図 ることができる。  Further, in the fifth light source device of the present invention, each of the plurality of optical fibers constitutes an optical fiber amplifier in which each of the plurality of light beams incident on the plurality of optical fibers is light to be amplified. The configuration may be an optical fiber through which the target light is guided. In such a case, since the light incident on each optical fiber is amplified from each optical fiber and emitted from each optical fiber, each of them has high intensity and the same polarization as the light emitted from the polarization direction conversion device. A plurality of linearly polarized light beams having directions can be obtained. As a result, it is possible to increase the amount of emitted light as a light source device.
この場合において、 前記光ファイバは、 希土類元素が添加されたフォスフエ ィ卜ガラス及び酸化ビスマス系ガラスのいずれかを主材として形成されている こととすることができる。  In this case, the optical fiber may be formed mainly of one of a phosphite glass to which a rare earth element is added and a bismuth oxide-based glass.
本発明の第 5の光源装置では、 前記複数の光ファイバに入射する前記複数の 光束それぞれは、パルス光列であることとすることができる。かかる場合には、 各パルス光列における光パルスの繰リ返し周期やパルス高を調整することによ リ、 光源装置としての射出光の光量を精度良く制御することができる。 In the fifth light source device of the present invention, each of the plurality of light beams incident on the plurality of optical fibers may be a pulse light train. In such cases, By adjusting the repetition period and pulse height of the light pulse in each pulse light train, the amount of emitted light as a light source device can be controlled with high accuracy.
本発明の第 5の光源装置では、 前記複数の光フアイバに入射する前記複数の 光束それぞれは、 前記複数の光ファイバへ入射する前に 1段以上の光ファイバ 増幅器によって増幅された光束であることとすることができる。 かかる場合に は、 1段以上の光ファイバ増幅器による 1段又は多段の光増幅作用により、 光 源装置としての射出光光量の増大を図ることができる。  In the fifth light source device of the present invention, each of the plurality of light beams incident on the plurality of optical fibers is a light beam amplified by one or more stages of optical fiber amplifiers before being incident on the plurality of optical fibers. It can be. In such a case, the amount of emitted light as a light source device can be increased by one-stage or multi-stage optical amplification by one or more stages of optical fiber amplifiers.
本発明の第 5の光源装置では、 偏光調整装置が、 偏光方向変換装置の直前に 配置された前記複数の光ファイバそれぞれに印加する機械的なストレス等を調 整して、 偏光方向変換装置に入射する複数の光束の偏光状態を調整することも 可能であるが、 前記偏光調整装置が、 前記複数の光ファイバよりも上流側に配 置された光学部品の光特性を制御して偏光調整を行う構成とすることができる。 かかる場合には、 偏光方向変換装置の直前に配置された複数の光ファイバが、 光増幅部を有する、 増幅対象光が導波される光ファイバであり、 ス卜レスの印 加等による偏光調整になじまない場合であっても、 より上流側に配置された偏 光調整がよリしゃすい光学部品の光特性を制御することにより、 偏光方向変換 装置に入射する複数の光束の偏光状態を揃えることができる。  In the fifth light source device of the present invention, the polarization adjusting device adjusts a mechanical stress or the like applied to each of the plurality of optical fibers disposed immediately before the polarization direction changing device, and adjusts the polarization direction changing device. It is also possible to adjust the polarization state of the plurality of incident light beams.However, the polarization adjusting device controls the optical characteristics of optical components disposed upstream of the plurality of optical fibers to adjust the polarization. The configuration can be performed. In such a case, the plurality of optical fibers disposed immediately before the polarization direction conversion device are optical fibers having an optical amplifier and guiding the light to be amplified, and the polarization is adjusted by applying stress or the like. Even if it does not fit well, the polarization adjustment located on the more upstream side controls the optical characteristics of the optical components that are slower, so that the polarization state of multiple light beams incident on the polarization direction conversion device is aligned. be able to.
本発明の第 5の光源装置では、 前記複数の光ファイバが、 互いにほぼ並行し て束ねられている構成とすることができる。 かかる場合には、 複数の光フアイ バが占有する区間を小さくするとともに、 偏光方向変換装置の受光面積を小さ くできるので、 光源装置の小型化を図ることができる。  In the fifth light source device of the present invention, the plurality of optical fibers may be bundled substantially in parallel with each other. In such a case, the section occupied by the plurality of optical fibers can be reduced, and the light receiving area of the polarization direction conversion device can be reduced, so that the light source device can be downsized.
本発明の第 5の光源装置では、前記偏光方向変換装置から射出された光束を、 少なくとも 1つの非線形光学結晶を介させることにより、 波長変換を行う波長 変換器を更に備える構成とすることができる。 かかる場合には、 偏光方向変換 装置から射出される光束の偏光方向を非線型光学結晶による波長変換 (倍高調 波発生、 和周波発生) が効率的に行われる入射光の偏光方向に設定することに より、 効率的に波長変換された光を発生して射出することができる。 The fifth light source device according to the present invention may further include a wavelength converter that performs wavelength conversion by passing the light beam emitted from the polarization direction conversion device through at least one nonlinear optical crystal. . In such a case, the polarization direction of the light beam emitted from the polarization direction conversion device should be set to the polarization direction of the incident light at which the wavelength conversion (double harmonic generation, sum frequency generation) is performed efficiently by the nonlinear optical crystal. To Thus, the wavelength-converted light can be generated and emitted more efficiently.
ここで、 前記複数の光ファイバから射出される光は赤外域及び可視域のいず れかの波長を有し、 前記波長変換器から射出される光は紫外域の波長を有する こととすることができる。 かかる場合には、 微細パターンの転写に適した紫外 光を効率的に発生することができる。  Here, the light emitted from the plurality of optical fibers has one of infrared and visible wavelengths, and the light emitted from the wavelength converter has an ultraviolet wavelength. Can be. In such a case, ultraviolet light suitable for transferring a fine pattern can be efficiently generated.
この場合には、 前記複数の光ファイバから射出される光は 1 5 4 7 n m付近 の波長を有し、 前記波長変換器から射出される光は 1 9 3 . 4 n m付近の波長 を有することとすることができる。 かかる場合には、 A r Fエキシマレーザ光 源を使用した場合に得られる波長の光を効率的に得ることができる。  In this case, the light emitted from the plurality of optical fibers has a wavelength of about 147 nm, and the light emitted from the wavelength converter has a wavelength of about 193.4 nm. It can be. In such a case, it is possible to efficiently obtain light having a wavelength obtained when the ArF excimer laser light source is used.
本発明は、 第 6の観点からすると、 希土類元素が添加されたフォスフェイ卜 ガラス及び酸化ビスマス系ガラスのいずれかを主材とする光導波路部材を含み、 入射光を増幅する光増幅器と;前記光増幅器から射出された光の波長を変換す る波長変換器と;を備える第 6の光源装置である。  According to a sixth aspect of the present invention, there is provided an optical amplifier that includes an optical waveguide member mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass, and amplifies incident light; A wavelength converter that converts a wavelength of light emitted from the amplifier.
これによれば、 シリカガラスを主材とし、 希土類元素が添加された、 従来の 増幅用ファイバ等のような光導波路部材に代えて、 フォスフェイ卜ガラス又は 酸化ビスマス系ガラスを主材とし、 高密度に希土類元素が添加された光導波路 部材を使用するので、 短い長さの光導波路部材によって高い増幅率で入射光を 増幅することができる。 このため、 光導波路部材を経由することによって発生 する偏光状態の変化を低減しつつ、 高輝度の光を波長変換器に供給することが できる。 また、 増幅にあたって光が経由する経路の長さが短くなるので、 誘導 ラマン散乱や自己位相変調によるスぺクトルの広がりも抑制することができる。 したがって、 簡易な構成で狭帯域の波長変換光を効率良く発生することができ る。  According to this, instead of a conventional optical waveguide member such as an amplification fiber or the like, which is mainly made of silica glass and to which a rare earth element is added, it is mainly made of phosphate glass or bismuth oxide-based glass. Since an optical waveguide member to which a rare earth element is added is used, incident light can be amplified with a high amplification factor by an optical waveguide member having a short length. For this reason, it is possible to supply high-luminance light to the wavelength converter while reducing the change in the polarization state caused by passing through the optical waveguide member. In addition, since the length of the path through which light passes during amplification is reduced, the spread of the spectrum due to stimulated Raman scattering and self-phase modulation can be suppressed. Therefore, it is possible to efficiently generate narrow-band wavelength converted light with a simple configuration.
本発明の第 6の光源装置では、 前記光導波路部材を、 光を導波するコアと、 前記コアの周囲に設けられたクラッドとを有する光ファイバとする構成とする ことができる。 また、 このファイバは、 2重クラッド構造を持つダブル ·クラ ッド ·ファイバの構造でもよい。 かかる場合には、 光の引き回しに使用される 伝搬用ファイバとの接続等が容易となり、 より簡易に光源装置を実現できる。 In the sixth light source device of the present invention, the optical waveguide member may be configured as an optical fiber having a core for guiding light and a clad provided around the core. This fiber also has a double clad double clad structure. It may be a double fiber structure. In such a case, connection to a propagation fiber used for guiding light becomes easy, and a light source device can be realized more easily.
ここで、前記光ファイバを直線状に敷設することができる。かかる場合には、 偏光状態の変化の原因となる径方向の応力の非対称性の発生を防止することが できるので、 入射時の偏光状態を維持した出力光を得ることができる。  Here, the optical fiber can be laid in a straight line. In such a case, it is possible to prevent the occurrence of radial stress asymmetry which causes a change in the polarization state, so that it is possible to obtain output light that maintains the polarization state at the time of incidence.
また、 前記光増幅器が、 少なくとも前記光ファイバを収容する容器を更に含 む構成とすることができる。 かかる場合には、 偏光状態の変化の原因となる増 幅用フアイバの周囲環境の変化を防止することができるので、 安定した波長変 換を行うことができる。  Further, the optical amplifier may further include a container accommodating at least the optical fiber. In such a case, it is possible to prevent a change in the surrounding environment of the amplification fiber, which causes a change in the polarization state, so that stable wavelength conversion can be performed.
本発明の光源装置では、 前記波長変換器が、 入射光の波長変換を行う少なく とも 1つの非線形光学結晶を含む構成とすることができる。 かかる場合には、 非線形光学結晶に、光増幅器から射出された高輝度の光を照射することによリ、 高出力の波長変換光を得ることができる。  In the light source device of the present invention, the wavelength converter may be configured to include at least one nonlinear optical crystal that performs wavelength conversion of incident light. In such a case, high-output wavelength-converted light can be obtained by irradiating the nonlinear optical crystal with high-luminance light emitted from the optical amplifier.
本発明は、 第 7の観点からすると、 レーザ光源から発振されるレーザ光の中 心波長を所定の設定波長に維持するための波長安定化制御方法であって、 前記 レーザ光の波長を検出する波長検出装置の検出基準波長の温度依存性を予め測 定する第 1工程と;前記設定波長に近い絶対波長を提供する絶対波長提供源か ら提供される絶対波長に対して前記波長検出装置の検出基準波長をほぼ一致さ せる絶対波長キャリブレーションを行う第 2工程と;前記第 1工程で求めた前 記温度依存性に基づいて、 前記波長検出装置の前記検出基準波長を前記設定波 長に設定する第 3工程とを含む波長安定化制御方法である。  According to a seventh aspect of the present invention, there is provided a wavelength stabilization control method for maintaining a center wavelength of a laser beam oscillated from a laser light source at a predetermined set wavelength, wherein the wavelength of the laser beam is detected. A first step of preliminarily measuring the temperature dependence of the detection reference wavelength of the wavelength detection device; and a method of using the wavelength detection device with respect to an absolute wavelength provided from an absolute wavelength providing source that provides an absolute wavelength close to the set wavelength. A second step of performing an absolute wavelength calibration to make the detection reference wavelengths substantially coincide with each other; and setting the detection reference wavelength of the wavelength detection device to the set wavelength based on the temperature dependency obtained in the first step. This is a wavelength stabilization control method including a third step of setting.
ここで、 「設定波長に近い絶対波長」は、設定波長と同一の波長も含む概念で ある。  Here, the “absolute wavelength close to the set wavelength” is a concept including the same wavelength as the set wavelength.
これによれば、 第 1工程でレーザ光の波長を検出する波長検出装置の検出基 準波長の温度依存性を予め測定しておく。 次いで、 第 2工程で設定波長に近い 絶対波長を提供する絶対波長提供源から提供される絶対波長に対して波長検出 装置の検出基準波長をほぼ一致させる絶対波長キヤリブレーションを行う。 そ して、 第 3工程で第 1工程で求めた温度依存性に基づいて、 波長検出装置の検 出基準波長を設定波長に設定する。 このように、 本発明によれば、 予め測定し た波長検出装置の検出基準波長の温度依存性を用いて、 絶対波長キヤリブレー ション後の波長検出装置の検出基準波長を設定波長に設定するので、 常に確実 に波長検出装蘆の検出基準波長を設定波長に正確に設定することができ、 これ によリ波長検出装置の雰囲気の温度等が変動しても、 それに影響を受けること なく、 波長検出装置を用いてレーザ光の中心波長を所定の設定波長に確実に維 持するような波長安定化制御が可能になる。 According to this, the temperature dependence of the detection reference wavelength of the wavelength detection device that detects the wavelength of the laser light in the first step is measured in advance. Next, in the second step, wavelength detection is performed for the absolute wavelength provided by the absolute wavelength source that provides the absolute wavelength close to the set wavelength. Absolute wavelength calibration is performed so that the detection reference wavelength of the device is almost the same. Then, based on the temperature dependency obtained in the first step in the third step, the detection reference wavelength of the wavelength detector is set to the set wavelength. As described above, according to the present invention, the detection reference wavelength of the wavelength detection device after the absolute wavelength calibration is set to the set wavelength using the temperature dependency of the detection reference wavelength of the wavelength detection device measured in advance. The detection reference wavelength of the wavelength detecting device can always be accurately set to the set wavelength, so that even if the temperature of the atmosphere of the wavelength detecting device fluctuates, the wavelength can be detected without being affected by the fluctuation. Using the device, wavelength stabilization control that ensures that the center wavelength of the laser beam is maintained at a predetermined set wavelength becomes possible.
この場合において、 前記波長検出装置が、 フアブリペロー ·ェタロンである 場合には、前記第 1工程で前記波長検出装置の共鳴波長の温度依存性を測定し、 前記第 2工程で前記波長検出装置の温度を制御することにより前記共鳴波長を 前記絶対波長にほぼ一致させ、 前記第 3工程で前記波長検出装置の温度を制御 することにより前記共鳴波長を前記設定波長に設定することとしても良い。 か かる場合には、 フアブリペロー ·エタロンの波長検出の基準となる共鳴波長の 温度依存性を利用して、 その共鳴波長 (検出基準波長) を設定波長に設定する ことが可能となる。  In this case, when the wavelength detection device is a Fabry-Perot etalon, the temperature dependence of the resonance wavelength of the wavelength detection device is measured in the first step, and the temperature of the wavelength detection device is measured in the second step. The resonance wavelength may be set to substantially coincide with the absolute wavelength by controlling the temperature, and the temperature of the wavelength detection device may be controlled in the third step to set the resonance wavelength to the set wavelength. In such a case, it is possible to set the resonance wavelength (detection reference wavelength) to the set wavelength by utilizing the temperature dependence of the resonance wavelength, which is the reference for the wavelength detection of Fabry-Perot etalon.
この場合において、 前記絶対波長提供源が、 前記レーザ光が入射する吸収セ ルである場合には、 前記第 2工程では、 前記吸収セルの前記設定波長に最も近 い吸収線の吸収が最大となり、 かつ前記波長検出装置の透過率が最大となるよ うにすることとしても良い。  In this case, when the absolute wavelength providing source is an absorption cell on which the laser light is incident, in the second step, absorption of an absorption line closest to the set wavelength of the absorption cell becomes maximum. In addition, the transmittance of the wavelength detection device may be maximized.
ここで、 「設定波長に最も近い吸収線」には、 「設定波長と同一波長の吸収線」 も含まれる。  Here, “the absorption line closest to the set wavelength” includes “the absorption line having the same wavelength as the set wavelength”.
本発明の波長安定化制御方法では、 前記第 1工程では、 前記レーザ光の中心 波長の温度依存性をも予め計測し、 前記第 2工程では、 前記レーザ光の波長制 御をも併せて行うこととしても良い。 かかる場合には、 前述した絶対波長キヤ リプレーシヨンを、 レーザ光の波長制御を行わない場合に比べて短時間で完了 することができる。 In the wavelength stabilization control method of the present invention, in the first step, the temperature dependence of the center wavelength of the laser light is also measured in advance, and in the second step, the wavelength control of the laser light is also performed. It is good. In such a case, the absolute wavelength key Replenishment can be completed in a shorter time than when laser wavelength control is not performed.
本発明の波長安定化制御方法では、 前記第 3工程で前記検出基準波長が前記 設定波長に設定された前記波長検出装置の検出結果に基づいて前記レーザ光源 からの前記レーザ光の波長を制御する第 4工程を更に含んでいても良い。 かか る場合には、 その検出基準波長が設定波長に正確に設定された波長検出装置の 検出結果に基づいてレーザ光源からのレーザ光の波長を制御するので、 そのレ 一ザ光の波長を設定波長に安定的に維持することができる。  In the wavelength stabilization control method according to the present invention, the wavelength of the laser light from the laser light source is controlled based on a detection result of the wavelength detection device in which the detection reference wavelength is set to the set wavelength in the third step. A fourth step may be further included. In such a case, since the wavelength of the laser light from the laser light source is controlled based on the detection result of the wavelength detection device whose detection reference wavelength is accurately set to the set wavelength, the wavelength of the laser light is controlled. It can be stably maintained at the set wavelength.
本発明の波長安定化制御方法では、 前記レーザ光の波長制御は、 前記レーザ 光源の温度、 供給電流の少なくとも一方を制御することにより行うこととして も良い。 例えば、 D F B半導体レーザやファイバーレーザのような単一波長発 振レーザの場合、 温度制御によってレーザの発振波長を制御することもできる し、 D F B半導体レーザの場合、 供給電流 (ドライブ電流) の制御によっても レーザの発振波長を制御することもできる。  In the wavelength stabilization control method of the present invention, the wavelength control of the laser light may be performed by controlling at least one of a temperature of the laser light source and a supply current. For example, in the case of a single-wavelength oscillation laser such as a DFB semiconductor laser or a fiber laser, the oscillation wavelength of the laser can be controlled by controlling the temperature. In the case of a DFB semiconductor laser, the supply current (drive current) can be controlled. Also, the oscillation wavelength of the laser can be controlled.
本発明は、 第 8の観点からすると、 マスクに形成されたパターンを基板上に 転写する露光装置であって、 赤外域から可視域までの範囲内の単一波長のレー ザ光を発生する光発生部と;前記光発生部の出力段に並列に配置された複数の 光ファイバから成るファイバ群と;前記各光ファイバからの光出力を個別に才 ン ·オフすることにより前記ファイバ群から出力されるレーザ光の光量を制御 する光量制御装置と;前記各光ファイバから出力される前記レーザ光の波長を 変換し、 前記レーザ光の高調波である紫外光を出力する波長変換部と;前記波 長変換部から出力される前記紫外光を露光用照明光として前記マスクを照明す る照明光学系と;備える第 1の露光装置である。  According to an eighth aspect of the present invention, there is provided an exposure apparatus for transferring a pattern formed on a mask onto a substrate, wherein the exposure apparatus generates a single-wavelength laser beam within a range from an infrared region to a visible region. A generating unit; a fiber group composed of a plurality of optical fibers arranged in parallel at an output stage of the light generating unit; and an optical output from each of the optical fibers by individually turning on and off the optical output from each of the optical fibers. A light amount control device that controls the amount of laser light to be output; a wavelength conversion unit that converts the wavelength of the laser light output from each of the optical fibers and outputs ultraviolet light that is a harmonic of the laser light; An illumination optical system for illuminating the mask using the ultraviolet light output from the wavelength conversion unit as illumination light for exposure;
これによれば、 照明光学系により波長変換部から出力される紫外光を露光用 照明光としてマスクが照明され、 該マスクに形成されたパターンが基板上に転 写される。 この場合、 光量制御装置により、 マスクに照射される紫外光の光量 制御を必要な要請に応じて行うことができるので、 結果的に要求される露光量 制御を実現することができる。 According to this, the mask is illuminated with the ultraviolet light output from the wavelength conversion unit by the illumination optical system as illumination light for exposure, and the pattern formed on the mask is transferred onto the substrate. In this case, the amount of ultraviolet light applied to the mask by the light amount control device Since the control can be performed in response to a necessary request, the required exposure control can be realized as a result.
この場合おいて、 前記各光ファイバからの光出力のオン ·オフ状況に対応す る出力強度マップが予め記憶された記憶装置を更に備え、前記光量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前記各光フアイバからの光 出力を個別にオン ·オフすることにより前記ファイバ群から出力されるレーザ 光の光量を制御することとしても良い。 かかる場合には、 各光ファイバの出力 にばらつきがあってもファイバ群の光出力を設定光量にほぼ一致させることが できるとともに、 諸性能の異なる光ファイバを用いることも可能となる。  In this case, the apparatus further comprises a storage device in which an output intensity map corresponding to the ON / OFF state of the optical output from each of the optical fibers is stored in advance, and the light amount control device is configured to store the output intensity map and a predetermined setting. The light output from each of the optical fibers may be individually turned on / off based on the light amount to control the light amount of the laser light output from the fiber group. In such a case, even if there is a variation in the output of each optical fiber, the optical output of the fiber group can be made substantially equal to the set light amount, and optical fibers having various performances can be used.
本発明の第 1の露光装置では、 前記光発生部は、 単一波長のレーザ光を発生 する光源と、 該光源からの光を所定周波数のパルス光に変換して出力する光変 調器とを有する場合に、 前記光量制御装置は、 前記光変調器から出力される前 記パルス光の周波数を制御することにより、 前記フアイバ群から出力されるレ 一ザ光の光量を更に制御することとすることができる。 かかる場合には、 光量 制御装置により、 光ファイバ群を構成する各ファイバの光出力の個別オン ·ォ フによる段階的な光量制御に加えて、 各段階間の光量の微調整が光変調器から 出力されるパルス光の周波数の制御により可能になる。 結果的に光量の連続制 御が可能となり、 所定範囲内であれば設定光量が如何なる値に設定されても、 出力光の光量をその設定光量に一致させることが可能になる。 従って、 より高 精度な露光量制御が可能になる。  In the first exposure apparatus of the present invention, the light generation unit includes: a light source that generates laser light of a single wavelength; and an optical modulator that converts light from the light source into pulse light of a predetermined frequency and outputs the pulse light. Wherein the light quantity control device further controls the light quantity of the laser light output from the fiber group by controlling the frequency of the pulse light output from the optical modulator. can do. In such a case, in addition to the step-by-step light amount control by individually turning on and off the light output of each fiber constituting the optical fiber group, the light amount control device allows the light modulator to finely adjust the light amount between each stage. It becomes possible by controlling the frequency of the output pulse light. As a result, continuous control of the light amount is possible, and the light amount of the output light can be made to match the set light amount regardless of the set light amount within a predetermined range. Therefore, more accurate exposure amount control becomes possible.
本発明の第 1の露光装置では、 前記光量制御装置は、 前記光変調器から出力 される前記パルス光のピークパワーを制御することにより、 前記ファイバ群か ら出力されるレーザ光の光量を更に制御することとしても良い。 かかる場合に は、 光量制御装置により、 光ファイバ群を構成する各ファイバの光出力の個別 オン ·オフによる段階的な光量制御に加えて、 各段階間の光量の微調整が光変 調器から出力されるパルス光のピークパワーの制御により可能になる。 結果的 に光量の連続制御が可能となり、 所定範囲内であれば設定光量が如何なる値に 設定されても、 出力光の光量をその設定光量に一致させることが可能になる。 従って、 より高精度な露光量制御が可能になる。 In the first exposure apparatus of the present invention, the light amount control device further controls a light amount of the laser light output from the fiber group by controlling a peak power of the pulse light output from the optical modulator. It may be controlled. In such a case, in addition to the step-by-step light amount control by individually turning on and off the optical output of each fiber constituting the optical fiber group, the light amount control device makes fine adjustment of the light amount between each stage from the optical modulator. This is made possible by controlling the peak power of the output pulse light. Consequent The light quantity can be continuously controlled, and the light quantity of the output light can be made to coincide with the set light quantity regardless of the value of the set light quantity within a predetermined range. Therefore, more accurate exposure amount control becomes possible.
本発明は、 第 9の観点からすると、 マスクに形成されたパターンを基板上に 転写する露光装置であって、 単一波長の光を発生する光源と、 該光源からの光 を所定周波数のパルス光に変換して出力する光変調器とを有し、 赤外域から可 視域までの範囲内の単一波長のレーザ光を発生する光発生部と;前記光発生部 によって発生されたパルス光を増幅する少なくとも 1段のファイバ増幅器を含 む光増幅部と;前記光変調器から出力される前記パルス光の周波数を制御する ことにより前記フアイバ増幅器からの出力光の光量を制御する光量制御装置 と;前記光増幅部から出力されるレーザ光の波長を変換し、 前記レーザ光の高 調波である紫外光を出力する波長変換部と;前記波長変換部から出力される前 記紫外光を露光用照明光として前記マスクを照明する照明光学系と;を備える 第 2の露光装置である。  According to a ninth aspect of the present invention, there is provided an exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; A light generator that has a light modulator that converts the light into light and outputs the light, and that generates a laser light of a single wavelength within a range from an infrared region to a visible region; and a pulse light generated by the light generator. An optical amplifying unit including at least one stage fiber amplifier for amplifying light; and a light amount control device for controlling the amount of output light from the fiber amplifier by controlling the frequency of the pulse light output from the optical modulator. A wavelength conversion unit that converts the wavelength of the laser light output from the optical amplification unit and outputs ultraviolet light that is a harmonic of the laser light; and converts the ultraviolet light output from the wavelength conversion unit to the ultraviolet light. The illumination light for exposure An illumination optical system for illuminating the mask.
これによれば、 照明光学系により波長変換部から出力される紫外光を露光用 照明光としてマスクが照明され、 該マスクに形成されたパターンが基板上に転 写される。 この場合、 光量制御装置により、 マスクに照射される紫外光の光量 制御を必要な要請に応じて行うことができるので、 結果的に要求される露光量 制御を実現することができる。  According to this, the mask is illuminated using the ultraviolet light output from the wavelength conversion unit by the illumination optical system as illumination light for exposure, and the pattern formed on the mask is transferred onto the substrate. In this case, the light amount control device can control the light amount of the ultraviolet light applied to the mask in response to a necessary request, so that the required exposure amount control can be realized as a result.
本発明の第 2の露光装置では、 前記光量制御装置は、 前記光変調器から出力 される前記パルス光のピークパワーを制御することにより前記光増幅部からの 出力光の光量を更に制御することとしても良い。  In the second exposure apparatus of the present invention, the light amount control device further controls the light amount of the output light from the optical amplifying unit by controlling a peak power of the pulse light output from the optical modulator. It is good.
本発明は、 第 1 0の観点からすると、 マスクに形成されたパターンを基板上 に転写する露光装置であって、 単一波長の光を発生する光源と、 該光源からの 光を所定周波数のパルス光に変換して出力する光変調器とを有し、 赤外域から 可視域までの範囲内の単一波長のレーザ光を発生する光発生部と;前記光発生 部によって発生されたパルス光を増幅する少なくとも 1段のファイバ増幅器を 含む光増幅部と;前記光変調器から出力される前記パルス光のピークパワーを 制御することにより前記光増幅部からの出力光の光量を制御する光量制御装置 と;前記光増幅部から出力されるレーザ光の波長を変換し、 前記レーザ光の高 調波である紫外光を出力する波長変換部と;前記波長変換部から出力される前 記紫外光を露光用照明光として前記マスクを照明する照明光学系と;を備える 第 3の露光装置である。 According to a tenth aspect, the present invention provides an exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; A light generator that has a light modulator that converts the light into pulsed light and outputs the light, and that generates a single-wavelength laser light within a range from an infrared region to a visible region; An optical amplifying unit including at least one fiber amplifier for amplifying the pulse light generated by the unit; and an output light from the optical amplifying unit by controlling a peak power of the pulse light output from the optical modulator. A light amount control device that controls the light amount of the laser light; a wavelength conversion unit that converts the wavelength of the laser light output from the optical amplification unit and outputs ultraviolet light that is a harmonic of the laser light; An illumination optical system that illuminates the mask with the ultraviolet light output as illumination light for exposure.
これによれば、 照明光学系により波長変換部から出力される紫外光を露光用 照明光としてマスクが照明され、 該マスクに形成されたパターンが基板上に転 写される。 この場合、 光量制御装置により、 マスクに照射される紫外光の光量 制御を必要な要請に応じて行うことができるので、 結果的に要求される露光量 制御を実現することができる。  According to this, the mask is illuminated using the ultraviolet light output from the wavelength conversion unit by the illumination optical system as illumination light for exposure, and the pattern formed on the mask is transferred onto the substrate. In this case, the light amount control device can control the light amount of the ultraviolet light applied to the mask in response to a necessary request, so that the required exposure amount control can be realized as a result.
本発明は、 第 1 1の観点からすると、 マスクに形成されたパターンを基板上 に繰り返し転写する露光装置であって、 単一波長の光を発生する光源と、 前記 光源からの光をパルス光に変換する光変調器とを有する光発生部と;前記光発 生部によって発生されたパルス光を増幅する少なくとも 1段のファイバ増幅器 を含む光増幅部と;前記増幅されたパルス光を前記マスクに照射して、 該マス クを介して前記基板を露光する際に、 その露光対象領域の基板上の位置に応じ て前記光変調器を介して前記パルス光の周波数及びピークパワーの少なくとも 一方を制御する制御装置と;を備える第 4の露光装置である。  According to a first aspect, the present invention provides an exposure apparatus that repeatedly transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; and a pulse light that emits light from the light source. A light generator having an optical modulator for converting the pulse light into light; an optical amplifier including at least one fiber amplifier for amplifying the pulse light generated by the light generator; When exposing the substrate through the mask, at least one of the frequency and peak power of the pulse light is transmitted through the optical modulator in accordance with the position of the exposure target area on the substrate. And a control device for controlling.
これによれば、 光発生部では、 光源で発生した単一波長の光を光変調器によ りパルス光に変換することによりパルス光を発生し、 そのパルス光がフアイバ 増幅器を含む光増幅部によって増幅される。 そして、 制御装置により、 その増 幅されたパルス光をマスクに照射して、該マスクを介して基板を露光する際に、 その露光対象領域の基板上の位置に応じて光変調器を介してパルス光の周波数 及びピークパワーの少なくとも一方が制御され、 これによりマスクに照射され る光量、 ひいては基板の露光量が高精度に制御される。 従って、 本発明によれ ば、 基板上の露光対象領域の位置によらず、 常に適切な露光量制御が可能とな リ、 精度良くマスクのパターンを基板上に転写することが可能になる。 According to this, the light generator generates pulsed light by converting light of a single wavelength generated by the light source into pulsed light by an optical modulator, and the pulsed light is converted into an optical amplifier including a fiber amplifier. Is amplified by Then, the controller irradiates the mask with the amplified pulsed light, and when exposing the substrate through the mask, through the optical modulator according to the position of the exposure target area on the substrate. At least one of the frequency and peak power of the pulsed light is controlled, thereby irradiating the mask. The amount of light that is emitted, and thus the amount of exposure of the substrate, is controlled with high precision. Therefore, according to the present invention, it is possible to always appropriately control the exposure amount irrespective of the position of the exposure target area on the substrate, and it is possible to accurately transfer the mask pattern onto the substrate.
ここで 「露光対象領域」 とは、 基板上に露光すべきショット領域が複数ある 場合のそれぞれのショッ卜領域、 及び各ショッ卜領域内の異なる領域の双方を 含む概念である。従って、本発明によれば、いわゆるステツパ(スキャニング · ステツパを含む) における基板上の各ショッ卜領域毎のプロセスばらつきの補 正や走査型露光装置における 1ショッ卜領域内の線幅均一性の向上が可能にな る。  Here, the “exposure target area” is a concept including both shot areas when there are a plurality of shot areas to be exposed on the substrate, and different areas within each shot area. Therefore, according to the present invention, in a so-called stepper (including a scanning stepper), a process variation in each shot area on a substrate is corrected, and a line width uniformity in one shot area in a scanning exposure apparatus is improved. Is possible.
本発明は、 第 1 2の観点からすると、 マスクに形成されたパターンを基板上 に転写する露光装置であって、 単一波長の光を発生する光源と、 前記光源から の光をパルス光に変換する光変調器とを有する光発生部と;前記パルス光を増 幅する光ファイバ増幅器を少なくとも各 1段含み、 前記光発生部の出力段に並 列に配置された複数の光経路から成る光増幅部と;前記光増幅部からの前記パ ルス光を前記マスクに照射して、 該マスクを介して前記基板を露光する際に、 前記各光経路からの光出力を個別にオン ·オフすることにより前記光増幅部か ら出力されるパルス光の光量を制御する制御装置と;を備える第 5の露光装置 である。  According to a first aspect of the present invention, there is provided an exposure apparatus for transferring a pattern formed on a mask onto a substrate, comprising: a light source for generating light of a single wavelength; and light from the light source to pulse light. A light generating section having an optical modulator for conversion; and a plurality of optical paths including at least one optical fiber amplifier for amplifying the pulsed light and arranged in parallel at an output stage of the light generating section. An optical amplifier; irradiating the mask with the pulsed light from the optical amplifier, and exposing the substrate through the mask, individually turning on / off the optical output from each optical path; A control device for controlling the amount of pulsed light output from the optical amplifying unit.
これによれば、 光発生部では、 光源で発生した単一波長の光を光変調器によ りパルス光に変換することによりパルス光を発生し、 そのパルス光がファイバ 増幅器を含む光増幅部によって増幅される。 そして、 制御装置により、 その増 幅されたパルス光をマスクに照射して、該マスクを介して基板を露光する際に、 各光経路からの光出力を個別にオン ·オフすることにより光増幅部から出力さ れるパルス光の光量が制御され、 これによりマスクに照射される光量、 ひいて は基板の露光量が広い範囲に渡って段階的に制御される。 従って、 本発明によ れば、 複数枚の基板を繰り返し露光する露光装置における基板毎のレジス卜感 度等の違いに合わせた露光量制御が可能になる。 従って、 レジス卜感度等に影 響を受けることなく、 基板上にマスクパターンを要求される精度で転写するこ とが可能になる。 According to this, the light generator generates pulsed light by converting light of a single wavelength generated by the light source into pulsed light by an optical modulator, and the pulsed light is converted into an optical amplifier including a fiber amplifier. Is amplified by Then, the controller irradiates the mask with the amplified pulsed light, and when exposing the substrate through the mask, individually turns on / off the light output from each light path, thereby performing optical amplification. The amount of pulsed light output from the unit is controlled, whereby the amount of light applied to the mask and, consequently, the amount of exposure of the substrate is controlled stepwise over a wide range. Therefore, according to the present invention, the resist feeling for each substrate in an exposure apparatus that repeatedly exposes a plurality of substrates is provided. It is possible to control the exposure amount according to the difference in the degree and the like. Therefore, it is possible to transfer the mask pattern onto the substrate with the required accuracy without being affected by the resist sensitivity or the like.
この場合も、 制御装置は、 上記の如くその露光対象領域の基板上の位置に応 じて光変調器を介してパルス光の周波数及びピークパワーの少なくとも一方を 制御するようにしても良い。  Also in this case, the control device may control at least one of the frequency and the peak power of the pulse light via the optical modulator according to the position of the exposure target area on the substrate as described above.
本発明の第 4又は第 5の露光装置において、 前記光源は、 赤外域又は可視域 のレーザ光を発生し、 前記光増幅部で増幅された前記パルス光を紫外光に波長 変換する波長変換部を更に備えることとしても良い。  In the fourth or fifth exposure apparatus of the present invention, the light source generates a laser beam in an infrared region or a visible region, and a wavelength conversion unit that converts the wavelength of the pulse light amplified by the light amplification unit into ultraviolet light. May be further provided.
本発明は、 第 1 3の観点からすると、 レーザ光によりマスクを照明し、 該マ ' スクのパターンを基板上に転写する露光装置であって、 前記レーザ光を発振す るレーザ光源と、 前記レーザ光の中心波長を所定の設定波長に維持するための 波長安定化に関連する前記レーザ光の光学特性をモニタするビームモニタ機構 と、 前記設定波長に近い絶対波長を提供する絶対波長提供源とを有する光源装 置と;前記レーザ光源から発振される前記レーザ光の中心波長及び前記ビーム モニタ機構の検出基準波長の温度依存性の測定データから成る温度依存性マツ プが記憶された記憶装置と;前記絶対波長提供源から提供される絶対波長に対 して前記ビームモニタ機構の検出基準波長をほぼ一致させる絶対波長キヤリブ レーシヨンを行うとともに、 前記温度依存性マップに基づいて前記検出基準波 長を前記設定波長に一致させる設定波長キヤリブレーションを行う第 1の制御 装置と;前記光源装置から射出されるレーザ光の波長を前記設定波長キヤリブ レーシヨンが終了した前記ビームモニタ機構のモニタ結果に基づいてフィード バック制御しつつ、 前記レーザ光を前記マスクに照射して該マスクを介して前 記基板を露光する第 2の制御装置と;を備える第 6の露光装置である。  According to a thirteenth aspect, the present invention is an exposure apparatus that illuminates a mask with a laser beam and transfers a pattern of the mask onto a substrate, wherein the laser light source oscillating the laser beam; A beam monitoring mechanism for monitoring optical characteristics of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength; and an absolute wavelength providing source for providing an absolute wavelength close to the set wavelength. A light source device having a temperature dependency map comprising temperature measurement data of a center wavelength of the laser light oscillated from the laser light source and a detection reference wavelength of the beam monitoring mechanism. Performing an absolute wavelength calibration to make the detection reference wavelength of the beam monitor mechanism substantially coincide with the absolute wavelength provided by the absolute wavelength providing source; A first control device for performing a set wavelength calibration for matching the detection reference wavelength to the set wavelength based on the temperature dependence map; and a control device for setting the wavelength of the laser beam emitted from the light source device to the set wavelength calibration. A second control device for irradiating the mask with the laser beam and exposing the substrate through the mask while performing feedback control based on the monitoring result of the beam monitoring mechanism for which the radiation has been completed. This is the sixth exposure apparatus.
これによれば、 第 1の制御装置により絶対波長提供源から提供される絶対波 長に対してビームモニタ機構の検出基準波長をほぼ一致させる絶対波長キヤリ プレーシヨン、 及び記憶装置に記憶された温度依存性マップ (レーザ光源から 発振されるレーザ光の中心波長及びビームモニタ機構の検出基準波長の温度依 存性の測定データから成る) に基づいて検出基準波長を設定波長に一致させる 設定波長キャリブレーションが行われる。 このようにして、 既知のビー厶モニ タ機構の検出基準波長の温度依存性を用いて、 絶対波長キヤリブレーション後 のビームモニタ機構の検出基準波長を設定波長に一致させることができる。 そ して、 第 2の制御装置では、 光源装置から射出されるレーザ光の波長を設定波 長キヤリプレーションが終了したビームモニタ機構のモニタ結果に基づいてフ イードバック制御しつつ、 レーザ光をマスクに照射して該マスクを介して基板 を露光する。 従って、 ビームモニタ機構のモニタ結果に基づいてレーザ光の中 心波長を所定の設定波長に確実に維持するような波長安定化制御を行いつつ、 レーザ光をマスクに照射して該マスクを介して基板を露光することができるの で、 雰囲気の温度変動等の影響の少ない高精度な露光が可能になる。 According to this, the absolute wavelength carrier for making the detection reference wavelength of the beam monitor mechanism substantially coincide with the absolute wavelength provided from the absolute wavelength providing source by the first control device. And a temperature dependency map stored in the storage device (consisting of measurement data of the temperature dependency of the center wavelength of the laser light emitted from the laser light source and the detection reference wavelength of the beam monitoring mechanism). The set wavelength calibration for matching the wavelength to the set wavelength is performed. In this manner, the detection reference wavelength of the beam monitor mechanism after the absolute wavelength calibration can be made to coincide with the set wavelength by using the temperature dependence of the detection reference wavelength of the known beam monitor mechanism. Then, the second control device controls the wavelength of the laser beam emitted from the light source device based on the monitoring result of the beam monitor mechanism after the completion of the set wavelength calibration, and controls the laser beam while performing feedback control. The substrate is exposed through the mask by irradiating the mask. Therefore, while performing wavelength stabilization control to ensure that the center wavelength of the laser beam is maintained at the predetermined set wavelength based on the monitoring result of the beam monitoring mechanism, the laser beam is irradiated onto the mask and is passed through the mask. Since the substrate can be exposed, it is possible to perform high-precision exposure with little influence of temperature fluctuation of the atmosphere.
この場合において、 前記マスクから出射された前記レーザ光を前記基板に投 射する投影光学系と;前記投影光学系の近傍の環境に関連する物理量を測定す る環境センサとを更に備える場合、 前記第 2の制御装置により前記基板の露光 が開始されてから所定のタイミング毎に、 前記環境センサの計測値に基づいて 標準状態からの前記物理量の変化に起因する前記投影光学系の結像特性の変動 分をほぼ相殺するための波長変更量を計算で求め、 該波長変更量に応じて前記 設定波長を変更する第 3の制御装置とを更に備えることとすることができる。 投影光学系の設置環境に関連する物理量 (周囲気体の圧力、 温度、 湿度など) が標準状態から変動すると、 大気の屈折率が変動し、 これにより投影光学系が 本来それに合わせて調整されていた露光波長 (設定波長) が変動し、 露光光で あるレーザ光の波長がもとのまま投影光学系に照射されると、 投影光学系の結 像特性に前記物理量の変動に起因する諸収差 (色収差を含む) が発生する。 本 発明によれば、 かかる場合に、 第 3の制御装置が、 基板の露光が開始されてか ら所定のタイミング毎に、 環境センサの計測値に基づいて標準状態からの前記 物理量の変化に起因する投影光学系の結像特性の変動分をほぼ相殺するための 波長変更量を計算で求め、 該波長変更量に応じて設定波長を変更する。 この結 果、 投影光学系の諸収差が同時に補正され、 第 2の制御装置がその変更後の設 定波長を基準としてビームモニタ機構を用いてレーザ光の中心波長を所定の設 定波長に確実に維持するような波長安定化制御を行いつつ、 レーザ光をマスク に照射する。 これにより、 マスクから出射したレーザ光が投影光学系により基 板上に投射され基板が露光される。 この場合、 結果的に環境条件に関連する物 理量の変動が存在しなかったかのような状態 (すなわち、 結像特性の変動量が 相殺された状態) で、 精度良く露光が行われることとなる。 In this case, when further comprising: a projection optical system that projects the laser beam emitted from the mask onto the substrate; and an environment sensor that measures a physical quantity related to an environment near the projection optical system. At every predetermined timing after the exposure of the substrate is started by the second control device, based on the measurement value of the environment sensor, the imaging characteristic of the projection optical system caused by the change of the physical quantity from a standard state is determined based on the measurement value of the environment sensor. The apparatus may further include a third control device for calculating a wavelength change amount for almost canceling the variation, and changing the set wavelength according to the wavelength change amount. If the physical quantities related to the installation environment of the projection optical system (pressure, temperature, humidity, etc. of the surrounding gas) fluctuate from the standard state, the refractive index of the atmosphere fluctuates, and the projection optical system was originally adjusted to match it When the exposure wavelength (set wavelength) fluctuates and the wavelength of the laser light as the exposure light is irradiated onto the projection optical system as it is, various aberrations (due to the fluctuation of the physical quantity due to the fluctuation of the physical quantity) appear in the imaging characteristics of the projection optical system. (Including chromatic aberration). According to the present invention, in such a case, the third control device determines whether exposure of the substrate is started. At each predetermined timing, a wavelength change amount for substantially canceling a change in the imaging characteristic of the projection optical system due to a change in the physical quantity from the standard state based on the measurement value of the environment sensor is calculated, The set wavelength is changed according to the wavelength change amount. As a result, various aberrations of the projection optical system are corrected at the same time, and the second controller reliably uses the beam monitor mechanism to set the center wavelength of the laser beam to the predetermined set wavelength based on the changed set wavelength. The laser beam is applied to the mask while performing wavelength stabilization control to maintain the laser beam. Thus, the laser light emitted from the mask is projected on the substrate by the projection optical system, and the substrate is exposed. In this case, as a result, exposure can be performed with high accuracy in a state where there is no change in physical quantity related to environmental conditions (that is, a state in which the change in imaging characteristics is offset). .
例えば、物理量が大気圧を含む場合、標準状態における大気圧(標準大気圧) は任意で良いが、 例えば投影光学系などの光学性能 (投影光学系の結像特性を 含む) が最良となるようにその調整を行うときの基準となる大気圧であること が望ましく、 この場合には、 標準大気圧では投影光学系などの光学性能の変動 量が零となる。 通常、 標準大気圧は、 露光装置が設置される納入先(工場など) の平均大気圧に設定されることが多い。従って、露光装置を製造する組立地と、 露光装置が設置される納入先 (移設地) とに標高差があるときは、 例えば標準 大気圧 (平均大気圧など) 下に投影光学系などが設置されているかのように、 組立地ではその標高差に対応する波長だけ露光波長をシフ卜させた上で投影光 学系などの調整を行い、 移設地ではその波長を露光波長に戻す、 あるいは組立 地では露光波長のもとで投影光学系などの調整を行い、 移設地でその標高差を 相殺するように露光波長をシフ卜させる。  For example, when the physical quantity includes the atmospheric pressure, the atmospheric pressure in the standard state (standard atmospheric pressure) may be arbitrary, but for example, the optical performance of the projection optical system (including the imaging characteristics of the projection optical system) is best. It is desirable that the atmospheric pressure be a reference when the adjustment is made. In this case, the fluctuation amount of the optical performance of the projection optical system and the like becomes zero at the standard atmospheric pressure. Normally, the standard atmospheric pressure is often set to the average atmospheric pressure of the delivery destination (factory, etc.) where the exposure apparatus is installed. Therefore, if there is an elevation difference between the assembly site where the exposure equipment is manufactured and the delivery destination (relocation location) where the exposure equipment is installed, for example, a projection optical system is installed under standard atmospheric pressure (such as average atmospheric pressure). At the assembly site, the exposure wavelength is shifted by the wavelength corresponding to the elevation difference, and then the projection optical system is adjusted.At the relocation site, the wavelength is returned to the exposure wavelength, or On the ground, the projection optical system is adjusted under the exposure wavelength, and the exposure wavelength is shifted so that the altitude difference is offset at the relocation site.
なお、 投影光学系が空気以外の気体中に設置される場合、 上記の 「大気圧」 はその投影光学系の周囲の気体の圧力となる。  When the projection optical system is installed in a gas other than air, the above “atmospheric pressure” is the pressure of the gas around the projection optical system.
ここで、 本発明では、 例えば投影光学系によって照明光の波長を変更するこ とと、 その投影光学系の設置環境 (周囲の気体の圧力、 温度、 湿度など) を変 更することは実質的に等価であることを利用している。 このとき、 投影光学系 の屈折素子の硝材の種類が単一であるときには、 その等価性が完全に成立し、 硝材が複数種類であってもその等価性はほぼ成立する。 従って、 設置環境に対 する投影光学系 (特に屈折素子) の屈折率の変化特性を用いて、 照明光の波長 のみを変化させることによって、 実質的に投影光学系の設置環境が変化した場 合と等価な状態を実現することができる。 Here, in the present invention, for example, changing the wavelength of the illumination light by the projection optical system and changing the installation environment (pressure, temperature, humidity, etc. of the surrounding gas) of the projection optical system. Making use of the fact that changing is substantially equivalent. At this time, when the type of the glass material of the refraction element of the projection optical system is single, the equivalence is completely established, and even when there are a plurality of types of glass materials, the equivalence is almost satisfied. Therefore, when only the wavelength of the illuminating light is changed by using the change characteristic of the refractive index of the projection optical system (particularly the refractive element) with respect to the installation environment, when the installation environment of the projection optical system is substantially changed. Can be realized.
ここで、 前記所定のタイミングは、 所定枚数の基板の露光終了毎のタイミン グであっても良く、 基板上の 1ショッ卜の露光終了の度毎のタイミングであつ ても良くあるいは露光条件の変更の度毎のタイミングであっても良い。ここで、 所定枚数は 1枚であっても良く、 1ロットに相当する枚数であっても良い。 ま た、 露光条件の変更とは、 照明条件の変更の他、 マスクの交換等の広い意味で の露光に関する条件が変更された場合の全てを含む。  Here, the predetermined timing may be timing each time exposure of a predetermined number of substrates is completed, may be timing each time exposure of one shot on the substrate is completed, or may be a change in exposure conditions. May be the timing of each time. Here, the predetermined number may be one or may be a number corresponding to one lot. Further, the change of the exposure condition includes not only the change of the illumination condition but also all the cases where the condition regarding the exposure in a broad sense such as replacement of a mask is changed.
あるいは、 所定のタイミングは、 前記環境センサの計測値に基づいて得られ る環境に関連する物理量 (又はその変化量) が所定量以上変化したタイミング であっても良く、 あるいは投影光学系などの光学性能 (又はその変動量) を演 算する間隔 (例えば数 S ) に合わせて、 ほぼリアルタイムで行っても良い。 あるいは所定のタイミングは、 予め定めた所定の時間毎のタイミングであって も良い。  Alternatively, the predetermined timing may be a timing at which a physical quantity (or a change amount thereof) related to the environment obtained based on the measurement value of the environment sensor changes by a predetermined amount or more, or an optical system such as a projection optical system. It may be performed almost in real time according to the interval (for example, several S) at which the performance (or its variation) is calculated. Alternatively, the predetermined timing may be a timing at every predetermined time.
この場合において、 前記投影光学系の結像特性を補正する結像特性補正装置 を更に備え、 前記結像特性補正装置は、 前記第 3の制御装置による前記設定波 長の変更の度毎に、 前記設定波長の変更により補正される前記投影光学系の結 像特性の変動分を除く、 結像特性変動を補正することとしても良い。  In this case, the image processing apparatus further includes an imaging characteristic correction device that corrects an imaging characteristic of the projection optical system, wherein the imaging characteristic correction device changes the set wavelength each time the third control device changes the set wavelength. The imaging characteristic variation may be corrected except for the variation in the imaging characteristic of the projection optical system, which is corrected by changing the set wavelength.
ここで、 「設定波長の変更により補正される前記投影光学系の結像特性の変 動分を除く、 結像特性変動」 には、 設定波長の変更により前記物理量の変動に 起因する投影光学系の結像特性の変動が完全に補正されなかった場合には、 そ の補正されなかった、 前記物理量の変動に起因する投影光学系の結像特性の変 動分も含まれる。 Here, the “imaging characteristic change excluding the change in the imaging characteristic of the projection optical system corrected by the change in the set wavelength” includes the projection optical system caused by the change in the physical quantity due to the change in the set wavelength. If the change in the imaging characteristics of the projection optical system was not completely corrected, the change in the imaging characteristics of the projection optical system due to the change in the physical quantity was not corrected. The movement is also included.
かかる場合には、 前記物理量の変動に起因する投影光学系の結像特性の変動 分 (以下、 適宜 「環境変動分」 と呼ぶ) の大部分が上記の設定波長の変更によ り補正され、 その残りの環境変動分が他の照射変動分等とともに、 結像特性補 正装置により補正される。 この結果、 投影光学系の結像特性をほぼ完全に補正 した状態で高精度な露光が行われる。  In such a case, most of the change in the imaging characteristic of the projection optical system (hereinafter, appropriately referred to as “environmental change”) due to the change in the physical quantity is corrected by the change in the set wavelength, and The remaining environmental fluctuations are corrected by the imaging characteristic correction device together with other irradiation fluctuations. As a result, high-precision exposure is performed while the imaging characteristics of the projection optical system are almost completely corrected.
この場合において、 前記結像特性補正装置は、 前記第 3の制御装置による前 記設定波長の変更間では、 前記レーザ光の波長変動を考慮して前記結像特性変 動を補正することとしても良い。 設定波長の変更は上述した所定のタイミング で行われるが、 この設定波長の変更間隔が長いと、 その間で前記物理量の変動 が生じるので、 これに起因する環境変動分を結像特性補正装置が補正すること としたものである。  In this case, the imaging characteristic correction device may correct the imaging characteristic change in consideration of the wavelength change of the laser light during the change of the set wavelength by the third control device. good. The change of the set wavelength is performed at the above-mentioned predetermined timing. However, if the change interval of the set wavelength is long, the physical quantity fluctuates during that time, and the imaging characteristic correction device corrects the environmental fluctuation caused by this. It was decided to do so.
本発明の第 6の露光装置では、 投影光学系の近傍の環境に関連する物理量を 測定する環境センサとを更に備える場合、 前記環境センサは、 少なくとも大気 圧を検出することとしても良い。  When the sixth exposure apparatus of the present invention further includes an environment sensor that measures a physical quantity related to an environment near the projection optical system, the environment sensor may detect at least atmospheric pressure.
本発明の第 6の露光装置では、 前記光源装置は、 前記レーザ光源からのレー ザ光を増幅するファイバ増幅器と;前記増幅されたレーザ光の波長を紫外域の 波長に変換する非線形光学結晶を含む波長変換器を更に備えていても良い。 か かる場合には、 ファイバ増幅器によリレーザ光源からのレーザ光を増幅し、 こ の増幅されたレーザ光を波長変換器により紫外域の波長の光に波長変換するこ とが可能となる。 従って、 例えば、 要求される光量が大きい場合であっても、 小型のレーザ光源、 例えば、 D F B半導体レーザ、 ファイバーレーザ等の固体 レーザを用いても、 短波長の高工ネルギのエネルギビームを出力することが可 能となる。 光源装置の小型 ·軽量化、 ひいては露光装置のフッ卜プリン卜の狭 小化と、 露光の解像力の向上による微細パターンの基板上への高精度な転写が 可能になる。 本発明は、 第 1 4の観点からすると、 エネルギビームにより感光剤が塗布さ れた基板を露光する露光装置であって、 前記エネルギビームを発生するビーム 源と ;前記ビーム源から出力される前記エネルギビームの波長を変更する波長 変更装置と ;前記波長変更装置により前記波長が変更されたとき、 その波長変 更に伴って生じる前記感光剤の感度特性の変化量に応じて前記基板に与えられ る積算露光量を制御する露光量制御装置と ;を備える第 7の露光装置である。 これによれば、 波長変更装置により、 ビーム源から出力されるエネルギビー 厶の波長が変更されると、 露光量制御装置によりその波長変更に伴つて生じる 基板上の感光剤の感度特性の変化量に応じて基板に与えられる積算露光量が制 御される。 In a sixth exposure apparatus of the present invention, the light source device includes: a fiber amplifier that amplifies laser light from the laser light source; and a nonlinear optical crystal that converts a wavelength of the amplified laser light into a wavelength in an ultraviolet region. A wavelength converter may be further provided. In such a case, the laser light from the laser light source is amplified by the fiber amplifier, and the amplified laser light can be wavelength-converted into light in the ultraviolet region by the wavelength converter. Therefore, for example, even when the required light quantity is large, even if a small laser light source, for example, a solid-state laser such as a DFB semiconductor laser or a fiber laser is used, an energy beam of short wavelength and high energy is output. It becomes possible. This makes it possible to reduce the size and weight of the light source device and, consequently, reduce the footprint of the exposure device, and to transfer a fine pattern onto a substrate with high precision by improving the resolution of exposure. According to a fifteenth aspect, the present invention provides an exposure apparatus for exposing a substrate coated with a photosensitive agent by using an energy beam, comprising: a beam source for generating the energy beam; A wavelength changing device for changing the wavelength of the energy beam; and when the wavelength is changed by the wavelength changing device, the wavelength changing device is provided to the substrate in accordance with an amount of change in the sensitivity characteristic of the photosensitive agent accompanying the wavelength change. And a light exposure control device for controlling the integrated light exposure. According to this, when the wavelength of the energy beam output from the beam source is changed by the wavelength changing device, the change amount of the sensitivity characteristic of the photosensitive agent on the substrate caused by the change of the wavelength by the exposure amount control device. The integrated exposure amount given to the substrate is controlled in accordance with.
すなわち、 エネルギビームの波長を変更すると、 その波長の変更 (波長シフ 卜) によって基板上の感光剤 (レジス卜)の感度特性が変化することがあるが、 そのような場合に、 本発明では、 露光量制御装置により、 その波長変更に伴つ て生じる感光剤の感度特性の変化量に応じて基板に与えられる積算露光量を制 御することができる。 従って、 感光剤の感度特性の変化に影響されることのな い精度の良い露光が可能になる。  That is, when the wavelength of the energy beam is changed, the sensitivity characteristics of the photosensitive agent (resist) on the substrate may change due to the change in the wavelength (wavelength shift). The exposure amount control device can control the integrated exposure amount given to the substrate according to the amount of change in the sensitivity characteristic of the photosensitive agent caused by the wavelength change. Therefore, accurate exposure can be performed without being affected by changes in the sensitivity characteristics of the photosensitive agent.
本発明は、 第 1 5の観点からすると、 露光用ビームを基板に照射することに より、 所定のパターンを基板に転写する露光装置であって、 赤外域及び可視域 のいずれかの波長の光を射出する複数の光ファイバと ;前記複数の光ファイバ を介した同一波長の複数の光束の偏光状態を揃える偏光調整装置と ;前記複数 の光ファイバを介した全ての光束を同一の偏光方向を有する複数の直線偏光光 束に変換する偏光方向変換装置と ;前記偏光方向変換装置から射出された光束 を、少なくとも 1つの非線形光学結晶を介させることにより、波長変換を行い、 紫外域の波長の光を射出する波長変換器と;前記波長変換器から射出される光 を前記露光用ビームとして前記基板に照射する光学系と ;を備える第 8の露光 装置である。 これによれば、 複数の光ファイバ、 偏光調整装置及び波長変換器によって微 細パターンの転写に適した紫外光を効率的に発生することができ、 該紫外光が 光学系により露光用ビームとして基板に照射されるので、 効率的に所定のパタ ーンを基板に転写することができる。 According to a fifteenth aspect, the present invention is an exposure apparatus for transferring a predetermined pattern onto a substrate by irradiating the substrate with an exposure beam, wherein the light has a wavelength of any one of an infrared region and a visible region. A plurality of optical fibers for emitting light; a polarization adjusting device for aligning the polarization states of a plurality of light beams having the same wavelength through the plurality of optical fibers; A polarization direction conversion device for converting the light into a plurality of linearly polarized light beams having the same; An eighth exposure apparatus, comprising: a wavelength converter that emits light; and an optical system that irradiates the substrate with light emitted from the wavelength converter as the exposure beam. According to this, a plurality of optical fibers, a polarization adjusting device, and a wavelength converter can efficiently generate ultraviolet light suitable for transfer of a fine pattern, and the ultraviolet light is converted into an exposure beam by the optical system as a substrate. As a result, the predetermined pattern can be efficiently transferred to the substrate.
本発明は、 第 1 6の観点からすると、 露光光を基板に照射して所定のパター ンを形成する露光装置であって、 希土類元素が添加されたフォスフェイ卜ガラ ス及び酸化ビスマス系ガラスのいずれかを主材とする光導波路部材を含み、 入 射光を増幅する光増幅器と;前記光増幅器から射出された光の波長を変換する 波長変換器と;前記波長変換器から射出される光を前記露光光として前記基板 に照射する光学系と;を備える第 9の露光装置である。  According to a sixteenth aspect, the present invention relates to an exposure apparatus that forms a predetermined pattern by irradiating exposure light to a substrate, wherein the exposure apparatus includes a phosphate glass to which a rare earth element is added and a bismuth oxide glass. An optical amplifier that amplifies the incident light; a wavelength converter that converts the wavelength of the light emitted from the optical amplifier; and an optical amplifier that converts the light emitted from the wavelength converter. A ninth exposure apparatus comprising: an optical system that irradiates the substrate as exposure light.
この場合において、 前記光導波路部材は、 光を導波するコアと、 前記コアの 周囲に設けられたクラッドとを有する光ファイバであることとすることができ る。  In this case, the optical waveguide member may be an optical fiber having a core for guiding light and a clad provided around the core.
本発明の第 9の露光装置では、 前記波長変換器は、 2 0 0 n m以下の波長の 前記露光光を発生することとすることができる。 かかる場合には、 波長スぺク 卜ルの広がりが小さな 2 0 0 n m以下の波長の露光光を波長変換器から発生す ることにより、 精度の良い基板の露光を効率良く行うことでき、 2 0 0 n m以 下という短い波長に応じた微細なパターンを精度良く基板に形成することがで きる。  In a ninth exposure apparatus according to the present invention, the wavelength converter may generate the exposure light having a wavelength of 200 nm or less. In such a case, the exposure of the substrate with high accuracy can be performed efficiently by generating the exposure light having a wavelength of 200 nm or less, which has a small spread of the wavelength spectrum, from the wavelength converter. A fine pattern corresponding to a short wavelength of less than 100 nm can be accurately formed on a substrate.
なお、本発明の第 9の露光装置が所定のバタ一ンが形成されたマスクを有し、 光学系を介して基板を露光するときには、 露光光とほぼ同一の波長の光が使用 されるマスクの位置検出にあたって、 上記波長変換器が発生する光を使用する ことにより、 当該位置検出用の光を効率良く供給することが可能となる。  The ninth exposure apparatus of the present invention has a mask on which a predetermined pattern is formed, and when exposing a substrate via an optical system, a mask having substantially the same wavelength as the exposure light is used. By using the light generated by the wavelength converter in the position detection, it is possible to efficiently supply the position detection light.
本発明は第 1 7の観点からすると、 マスクに形成されたパターンを基板上に 繰り返し転写する露光方法であつて、 パルス光をフアイバ増幅器を用いて少な くとも 1回増幅する第 1工程と;前記増幅されたパルス光を前記マスクに照射 し、 該マスクを介して前記基板上の露光対象領域を露光する第 2工程と;前記 第 1工程の処理に先立って、 光源からのレーザ光を前記パルス光に変換すると ともに、 前記露光対象領域の基板上の位置に応じて前記パルス光の周波数及び ピークパワーの少なくとも一方を制御する第 3工程と;を含む第 1の露光方法 である。 According to a seventeenth aspect, the present invention relates to an exposure method for repeatedly transferring a pattern formed on a mask onto a substrate, and a first step of amplifying the pulsed light at least once using a fiber amplifier; Irradiating the mask with the amplified pulsed light A second step of exposing the exposure target area on the substrate via the mask; and, prior to the processing of the first step, converting a laser beam from a light source into the pulsed light, and exposing the exposure target area. A third step of controlling at least one of the frequency and peak power of the pulsed light according to the position on the substrate.
これによれば、 パルス光をファイバ増幅器を用いて少なくとも 1回増幅し、 その増幅されたパルス光をマスクに照射し、 該マスクを介して基板上の露光対 象領域を露光する。 この場合、 パルス光をファイバ増幅器を用いて増幅するの に先立って、 光源からのレーザ光をパルス光に変換するとともに、 露光対象領 域の基板上の位置に応じてパルス光の周波数及びピークパワーの少なくとも一 方を制御する。 従って、 パルス光をマスクに照射し、 該マスクを介して基板上 の露光対象領域を露光する際には、 露光対象領域の基板上の位置に応じて露光 量が調整された状態で露光が行われることになる。 従って、 本発明によれば、 基板上の露光対象領域の位置によらず、 常に適切な露光量制御が可能となり、 精度良くマスクのパターンを基板上に転写することが可能になる。  According to this, the pulsed light is amplified at least once by using a fiber amplifier, the amplified pulsed light is irradiated on a mask, and a region to be exposed on the substrate is exposed through the mask. In this case, prior to amplifying the pulsed light using the fiber amplifier, the laser light from the light source is converted into the pulsed light, and the frequency and the peak power of the pulsed light are determined according to the position of the exposure target area on the substrate. Control at least one of Therefore, when irradiating the mask with the pulse light and exposing the exposure target area on the substrate through the mask, the exposure is performed in a state where the exposure amount is adjusted according to the position of the exposure target area on the substrate. Will be Therefore, according to the present invention, it is possible to always appropriately control the exposure amount regardless of the position of the exposure target area on the substrate, and it is possible to transfer the mask pattern onto the substrate with high accuracy.
ここで 「露光対象領域」 とは、 基板上に露光すべきショット領域が複数ある 場合のそれぞれのショッ卜領域、 及び各ショッ卜領域内の異なる領域の双方を 含む概念である。従って、本発明によれば、いわゆるステツパ(スキャニング · ステツパを含む) における基板上の各ショッ卜領域毎のプロセスばらつきの補 正や走査型露光装置における 1ショッ卜領域内の線幅均一性の向上が可能にな る。  Here, the “exposure target area” is a concept including both shot areas when there are a plurality of shot areas to be exposed on the substrate, and different areas within each shot area. Therefore, according to the present invention, in a so-called stepper (including a scanning stepper), a process variation in each shot area on a substrate is corrected, and a line width uniformity in one shot area in a scanning exposure apparatus is improved. Is possible.
この場合において、 前記ファイバ増幅器が、 複数並列に設けられている場合 には、 前記第 1工程では、 選択されたファイバ増幅器のみを用いて前記パルス 光の増幅を行うこととしても良い。 かかる場合には、 露光量の制御を広いダイ ナミックレンジで段階的に行うことができるので、 上記の露光対象領域の基板 上の位置に応じてパルス光の周波数及びピークパワーの少なくとも一方を制御 する露光量制御との併用により、 より広い範囲に渡って露光量制御を高精度に 行なうことが可能になる。 上記のファイバ増幅器の選択を、 基板上のレジス卜 感度等に応じて行うことにより、 基板毎のレジス卜感度の違いに合わせた露光 量の制御が可能になる。 In this case, when the plurality of fiber amplifiers are provided in parallel, in the first step, the pulsed light may be amplified using only the selected fiber amplifier. In such a case, since the exposure amount can be controlled stepwise in a wide dynamic range, at least one of the frequency and the peak power of the pulsed light is controlled according to the position of the exposure target area on the substrate. When used together with the exposure control, the exposure control over a wider range can be performed with high accuracy. By selecting the fiber amplifier according to the resist sensitivity on the substrate and the like, it becomes possible to control the exposure amount according to the difference in the resist sensitivity for each substrate.
本発明の第 1の露光方法では、 前記光源は、 赤外域又は可視域のレーザ光を 発生し、 前記パルス光が前記マスクに照射される前に前記増幅されたパルス光 を紫外光に波長変換する第 4工程を更に含んでいても良い。  In the first exposure method of the present invention, the light source generates a laser light in an infrared region or a visible region, and wavelength-converts the amplified pulse light to ultraviolet light before the pulse light is applied to the mask. The method may further include a fourth step.
本発明は、 第 1 8の観点からすると、 レーザ光により基板を露光して所定の パターンを基板上に形成する露光方法であって、 露光開始に先立って、 前記レ 一ザ光の波長を検出する波長検出装置の検出基準波長の温度依存性を予め測定 する第 1副工程と、 前記設定波長に近い絶対波長を提供する絶対波長提供源か ら提供される絶対波長に対して前記波長検出装置の検出基準波長をほぼ一致さ せる絶対波長キャリブレーションを行う第 2副工程と、 前記第 1副工程で求め た前記温度依存性に基づいて、 前記波長検出装置の前記検出基準波長を前記設 定波長に設定する第 3副工程との処理を順次行う第 1工程と; しかる後、 前記 第 3副工程で前記検出基準波長が前記設定波長に設定された前記波長検出装置 の検出結果に基づいて前記レーザ光源からの前記レーザ光の波長を制御しつつ、 基板を前記レーザ光で繰り返し露光する第 2工程と;を含む第 2の露光方法で ある。  According to an eighteenth aspect, the present invention provides an exposure method for exposing a substrate with a laser beam to form a predetermined pattern on the substrate, wherein the wavelength of the laser light is detected prior to the start of exposure. A first sub-step of preliminarily measuring the temperature dependence of the detection reference wavelength of the wavelength detection device, and the wavelength detection device for an absolute wavelength provided from an absolute wavelength providing source that provides an absolute wavelength close to the set wavelength. A second sub-step of performing an absolute wavelength calibration to make the detection reference wavelengths substantially coincide with each other, and setting the detection reference wavelength of the wavelength detection device based on the temperature dependency obtained in the first sub-step. A first step of sequentially performing processing with a third sub-step of setting a wavelength; and thereafter, based on a detection result of the wavelength detecting device in which the detection reference wavelength is set to the set wavelength in the third sub-step. The laser light A second step of repeatedly exposing a substrate with the laser light while controlling the wavelength of the laser light from a source.
これによれば、 第 1工程の処理により、 予め測定した波長検出装置の検出基 準波長の温度依存性を用いて、 絶対波長キャリブレーション後の波長検出装置 の検出基準波長を設定波長に設定するので、 常に確実に波長検出装置の検出基 準波長が設定波長に正確に設定される。 そして、 第 2工程で、 検出基準波長が 設定波長に設定された波長検出装置の検出結果に基づいてレーザ光源からのレ 一ザ光の波長を制御しつつ、 基板がレーザ光で繰り返し露光される。 従って、 本発明によれば、 波長検出装置の雰囲気の温度等が変動しても、 それに影響を 受けることなく、 波長検出装置の検出基準波長を設定波長に正確に設定し、 そ の波長検出装置を用いてレーザ光の中心波長を所定の設定波長に確実に維持す るような波長安定化制御を行いつつ、 基板がレーザ光で繰り返し露光されるの で、 雰囲気の温度変動等の影響の少ない高精度な露光が可能になる。 According to this, in the process of the first step, the detection reference wavelength of the wavelength detection device after the absolute wavelength calibration is set to the set wavelength using the temperature dependence of the detection reference wavelength of the wavelength detection device measured in advance. Therefore, the detection reference wavelength of the wavelength detection device is always accurately set to the set wavelength. Then, in the second step, the substrate is repeatedly exposed to the laser light while controlling the wavelength of the laser light from the laser light source based on the detection result of the wavelength detection device in which the detection reference wavelength is set to the set wavelength. . Therefore, according to the present invention, even if the temperature or the like of the atmosphere of the wavelength detecting device fluctuates, it is not affected. Wavelength stabilization control that accurately sets the detection reference wavelength of the wavelength detector to the set wavelength without receiving it, and uses that wavelength detector to ensure that the center wavelength of the laser beam is maintained at the predetermined set wavelength. Since the substrate is repeatedly exposed to laser light while performing the process, high-precision exposure with little influence of temperature fluctuation of the atmosphere can be performed.
この場合において、 前記レーザ光の経路に配置された光学系が更に設けられ ている場合には、 前記光学系の光学性能の変動をキャンセルするために前記設 定波長を変更する第 3工程を更に含んでいても良い。 例えば大気圧の変動等が あると光学系の光学性能 (諸収差等) が変動することがあるが、 このような場 合に、 第 3工程において光学系の光学性能の変動をキャンセルするために設定 波長が変更される結果、 その変更後の設定波長を基準として波長検出装置を用 いてレーザ光の中心波長を所定の設定波長に確実に維持するような波長安定化 制御を行いつつ、基板をレーザ光で繰り返し露光することができる。このため、 結果的に大気圧の変動が存在しなかったかのような状態 (すなわち、 光学性能 の変動量が相殺された状態) で、 精度良く露光が行われることとなる。  In this case, when an optical system arranged in the path of the laser beam is further provided, a third step of changing the set wavelength in order to cancel a change in optical performance of the optical system is further performed. May be included. For example, when the atmospheric pressure fluctuates, the optical performance (various aberrations, etc.) of the optical system may fluctuate. In such a case, it is necessary to cancel the fluctuation of the optical performance of the optical system in the third step. As a result of the change in the set wavelength, the substrate is controlled while performing wavelength stabilization control using a wavelength detector to ensure that the center wavelength of the laser beam is maintained at the predetermined set wavelength, using the changed set wavelength as a reference. Exposure can be repeated with laser light. As a result, exposure can be performed with high accuracy in a state where the fluctuation of the atmospheric pressure does not exist (that is, the fluctuation of the optical performance is offset).
本発明は、 第 1 9の観点からすると、 露光光を、 光学系を介して基板に照射 して所定のパターンを形成する露光装置の製造方法において、 前記光学系の特 性の調整を、 本発明の第 6の光源装置が発生した前記露光光の波長を含む所定 幅の波長帯に属する波長の光を使用して行うことを特徴とする露光装置の製造 方法である。 これによれば、 露光にあたって露光光が介する光学系の特性の調 整を、 精度良くかつ簡易に行うことができる。  According to a nineteenth aspect, the present invention provides a method for manufacturing an exposure apparatus for irradiating a substrate with an exposure light through an optical system to form a predetermined pattern, the method comprising adjusting the characteristics of the optical system. A sixth aspect of the present invention is a method for manufacturing an exposure apparatus, wherein the method is performed using light having a wavelength belonging to a wavelength band having a predetermined width including the wavelength of the exposure light generated by the light source apparatus. According to this, it is possible to accurately and easily adjust the characteristics of the optical system through which the exposure light passes during the exposure.
また、 リソグラフイエ程において、 本発明の露光方法を用いて露光を行うこ とにより、基板上に複数層のパターンを重ね合せ精度良く形成することができ、 これにより、 より高集積度のマイクロデバイスを歩留まり良く製造することが でき、 その生産性を向上させることができる。 同様に、 リソグラフイエ程にお いて、 本発明の露光装置を用いて露光を行うことにより、 露光量制御精度の向 上により線幅制御精度が向上し、 これにより基板上に複数層のパターンを重ね 合せ精度良く形成することができる。 従って、 より高集積度のマイクロデバイ スを歩留まり良く製造することができ、その生産性を向上させることができる。 従って、 本発明は別の観点からすると、 本発明の露光方法又は本発明の露光装 置を用いるデバイス製造方法であり、 また、 該製造方法によって製造されたデ バイスであるとも言える。 図面の簡単な説明 Further, in the lithographic process, by performing exposure using the exposure method of the present invention, a pattern of a plurality of layers can be formed on a substrate with a high degree of superposition accuracy. Can be manufactured with high yield, and the productivity can be improved. Similarly, in the lithographic process, by performing exposure using the exposure apparatus of the present invention, the line width control accuracy is improved by the improvement of the exposure amount control accuracy, whereby the pattern of a plurality of layers is formed on the substrate. Pile It can be formed with high alignment accuracy. Therefore, a highly integrated microdevice can be manufactured with a high yield, and the productivity can be improved. Therefore, from another viewpoint, the present invention is a device manufacturing method using the exposure method of the present invention or the exposure apparatus of the present invention, and can be said to be a device manufactured by the manufacturing method. BRIEF DESCRIPTION OF THE FIGURES
図 1は、本発明の一実施形態に係る露光装置の構成を概略的に示す図である。 図 2は、 図 1の光源装置の内部構成を主制御装置とともに示すプロック図で ある。  FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to one embodiment of the present invention. FIG. 2 is a block diagram showing an internal configuration of the light source device of FIG. 1 together with a main control device.
図 3は、 図 2の光増幅部の構成を概略的に示す図である。  FIG. 3 is a diagram schematically showing a configuration of the optical amplifier of FIG.
図 4は、 光増幅部を構成する最終段のファイバ増幅器の出力端部が束ねられ て形成されたバンドル一ファイバの断面を示す図である。  FIG. 4 is a diagram showing a cross-section of a bundle-one fiber formed by bundling the output ends of the final-stage fiber amplifier constituting the optical amplification unit.
図 5は、 図 2の光増幅部を構成するファイバ増幅器及びその周辺部を、 波長 変換部の一部とともに概略的に示す図である。  FIG. 5 is a diagram schematically illustrating a fiber amplifier constituting the optical amplification unit in FIG. 2 and a peripheral portion thereof together with a part of a wavelength conversion unit.
図 6 Aは、 バンドル—ファイバ 1 7 3の出力端から射出される波長 1 . 5 4 4 t mの基本波を、 非線形光学結晶を用いて 8倍波 (高調波) に波長変換して 1 9 3 n mの紫外光を発生する波長変換部の構成例を示す図、 図 6 Bは、 バン ドル—ファイバ 1 7 3の出力端から射出される波長 1 . 5 7 mの基本波を非 線形光学結晶を用いて 1 0倍波に波長変換して 1 5 7 n mの紫外光を発生する 波長変換部の構成例を示す図である。  Figure 6A shows a bundle—the fundamental wave of 1.544 tm emitted from the output end of fiber 173 is converted to an 8th harmonic using a nonlinear optical crystal. Fig. 6B shows an example of the configuration of a wavelength conversion unit that generates 3 nm ultraviolet light. Fig. 6B shows the fundamental wave of 1.57 m emitted from the output end of the bundle fiber 173. FIG. 4 is a diagram showing a configuration example of a wavelength conversion unit that converts a wavelength into a 10th harmonic using a crystal and generates ultraviolet light of 157 nm.
図 7は、 変形例を説明するための図であって、 光増幅部の他の構成例を示す 図である。  FIG. 7 is a diagram for explaining a modified example, and is a diagram showing another configuration example of the optical amplifying unit.
図 8は、 本発明の係るデバイス製造方法の実施形態を説明するためのフロー チヤ一卜である。  FIG. 8 is a flowchart for explaining an embodiment of the device manufacturing method according to the present invention.
図 9は、図 8のステップ 2 0 4における処理のを示すフローチャートである。 発明を実施するための最良の形態 FIG. 9 is a flowchart showing the processing in step 204 of FIG. BEST MODE FOR CARRYING OUT THE INVENTION
以下、 本発明の一実施形態を図 1〜図 6に基づいて説明する。  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
図 1には、 本発明に係る光源装置を含んで構成された一実施形態に係る露光 装置 1 0の概略構成が示されている。この露光装置 1 0は、ステップ 'アンド ' スキャン方式の走査型露光装置である。  FIG. 1 shows a schematic configuration of an exposure apparatus 10 according to one embodiment including a light source device according to the present invention. The exposure apparatus 10 is a step-and-scan type scanning exposure apparatus.
この露光装置 1 0は、 光源装置 1 6及び照明光学系 1 2から成る照明系、 こ の照明系からの露光用照明光(以下、 「露光光」 という) I Lにより照明される マスクとしてのレチクル Rを保持するレチクルステージ R S T、 レチクル Rか ら射出された露光光 I Lを基板としてのウェハ W上に投射する投影光学系 P L、 ウェハ Wを保持する基板ステージとしての Zチル卜ステージ 5 8が搭載された X Yステージ 1 4、 及びこれらの制御系等を備えている。  The exposure apparatus 10 includes an illumination system including a light source device 16 and an illumination optical system 12, and a reticle as a mask illuminated by exposure illumination light (hereinafter, referred to as “exposure light”) IL from the illumination system. A reticle stage RST holding R, a projection optical system PL that projects the exposure light IL emitted from the reticle R onto the wafer W as a substrate, and a Z tilt stage 58 as a substrate stage holding the wafer W are mounted. XY stage 14 and their control systems.
前記光源装置 1 6は、 例えば、 波長 1 9 3 n m ( A r Fエキシマレーザ光と ほぼ同一波長)の紫外パルス光、 あるいは波長 1 5 7 n m ( F 2レーザ光とほぼ 同一波長) の紫外パルス光を出力する高調波発生装置である。 この光源装置 1 6は、 その少なくとも一部 (例えば、 後述の波長変換部など) が、 前記照明光 学系 1 2、 レチクルステージ R S T、投影光学系 P L、 Zチル卜ステージ 5 8、 X Yステージ 1 4及びこれら各部が搭載された不図示の本体コラム等から成る 露光装置本体とともに、 温度、 圧力、 湿度等が高精度に調整されたエンバイ口 ンメンタル,チャンバ (以下、 「チャンバ」 という) 1 1内に収容されている。 図 2には、 光源装置 1 6の内部構成が装置全体を統括制御する主制御装置 5 0とともにブロック図にて示されている。 この図 2に示されるように、 光源装 置 1 6は、 光源としてのレーザ光源を含む光源部 1 6 A、 レーザ制御装置 1 6 B、 光量制御装置 1 6 C、 及び偏光調整装置 1 6 D等を備えている。 The light source device 1 6 is, for example, a wavelength 1 9 3 nm (A r F excimer laser beam substantially the same wavelength) ultraviolet pulse (approximately the same wavelength as the F 2 laser beam) ultraviolet pulse light, or wavelength 1 5 7 nm of This is a harmonic generator that outputs light. The light source device 16 has at least a part thereof (for example, a wavelength conversion section described later), the illumination optical system 12, the reticle stage RST, the projection optical system PL, the Z tilt stage 58, and the XY stage 1 4 and an exposure apparatus main body including a main body column (not shown) on which these components are mounted, as well as an environmental instrument and chamber (hereinafter referred to as “chamber”) whose temperature, pressure, humidity, etc. are adjusted with high precision. Housed within. FIG. 2 is a block diagram showing the internal configuration of the light source device 16 together with a main control device 50 that controls the entire device. As shown in FIG. 2, the light source device 16 includes a light source section 16 A including a laser light source as a light source, a laser control device 16 B, a light amount control device 16 C, and a polarization adjusting device 16 D. Etc. are provided.
前記光源部 1 6 Aは、 光発生部としてのパルス光発生部 1 6 0、 光増幅部 1 6 1、 偏光方向変換装置としての四分の一波長板 1 6 2、 波長変換器としての 波長変換部 1 63、 ビームモニタ機構 1 64及び吸収セル 1 65等を含んで構 成されている。 The light source section 16A includes a pulse light generation section 160 as a light generation section, an optical amplification section 161, a quarter-wave plate 162 as a polarization direction conversion device, and a wavelength conversion section. It is configured to include a wavelength conversion section 163, a beam monitoring mechanism 164, an absorption cell 165, and the like.
前記パルス光発生部 1 60は、 レーザ光源 1 60 A、 光カップラ B S 1, B S 2、 光アイソレータ 1 60 B及び光変調器としての電気光学変調器 (以下、 ΓΕΟΜ」 という) 1 60 C等を有する。 なお、 レーザ光源 1 6 OAと波長変 換部 1 63との間の各要素間は光ファイバにより光学的に接続されている。 前記レーザ光源 1 6 OAとしては、 ここでは、単一波長発振レーザ、例えば、 発振波長 1. 544 / m、 連続波出力 (以下 「CW出力」 という) 20mWの I n G a A s P, D F B半導体レーザが用いられている。 以下においては、 レ 一ザ光源 1 60 Aを適宜「D F B半導体レーザ 1 60 A」とも呼ぶものとする。 ここで、 D F B半導体レーザとは、 縦モード選択性の低いフアプリ一ペロー 型共振器の代わりに、 回折格子を半導体レーザ内に作り上げたもので、 どのよ うな状況下であっても単一縦モード発振をするように構成されており、 分布帰 還型(Distributed Feedback: D F B)レーザと呼ばれるものである。 この様な レーザでは基本的に単一縦モード発振をすることから、 その発振スぺク卜ル線 幅は 0. 0 1 pm以下に抑えられる。  The pulse light generator 160 includes a laser light source 160 A, optical couplers BS 1 and BS 2, an optical isolator 160 B, and an electro-optical modulator (hereinafter referred to as ΓΕΟΜ) 160 C as an optical modulator. Have. In addition, each element between the laser light source 16 OA and the wavelength conversion unit 163 is optically connected by an optical fiber. As the laser light source 16 OA, here, a single-wavelength oscillation laser, for example, an oscillation wavelength of 1.544 / m, continuous wave output (hereinafter referred to as “CW output”) 20 mW of InGaAsP, DFB Semiconductor lasers are used. In the following, the laser light source 160A is also referred to as "DFB semiconductor laser 160A" as appropriate. Here, a DFB semiconductor laser is one in which a diffraction grating is built up in a semiconductor laser instead of a flat-peripheral resonator with low longitudinal mode selectivity. It is configured to oscillate and is called a distributed feedback (DFB) laser. Since such a laser basically oscillates in a single longitudinal mode, its oscillation spectrum line width can be suppressed to 0.01 pm or less.
また、 D F B半導体レーザは、 通常、 ヒー卜シンクの上に設けられ、 これら が筐体内に収容されている。 本実施形態では、 D F B半導体レーザ 1 6 OAに 付設されるヒー卜シンク上に温度調整器 (例えばペルチェ素子など) が設けら れており、 後述するように、 レーザ制御装置 1 6 Bがその溫度を制御すること により発振波長が制御 (調整) 可能な構成となっている。  The DFB semiconductor laser is usually provided on a heat sink, and these are housed in a housing. In the present embodiment, a temperature controller (for example, a Peltier element) is provided on a heat sink attached to the DFB semiconductor laser 16 OA. As described later, the laser controller 16 B By controlling the wavelength, the oscillation wavelength can be controlled (adjusted).
本実施形態では、 上記の発振波長の制御のため、 D F B半導体レーザ 1 60 Aの発振波長の温度依存性を予め測定し、 その測定結果を温度依存性マップと して主制御装置 50に併設された記憶装置としてのメモリ 5 1内に、 テーブル の形、 変換関数、 あるいは変換係数として格納 (記憶) している。  In this embodiment, in order to control the above-mentioned oscillation wavelength, the temperature dependence of the oscillation wavelength of the DFB semiconductor laser 160 A is measured in advance, and the measurement result is provided in the main controller 50 as a temperature dependence map. It is stored (stored) as a table shape, a conversion function, or a conversion coefficient in a memory 51 as a storage device.
ここでは、 D F B半導体レーザ 1 6 OAの発振波長は 0. 1 nm/°C程度の 温度依存性を持つものとする。 従って、 例えば、 DF B半導体レーザの温度を 1 °C変化させると、 基本波 (1 544 nm) ではその波長が 0. 1 n m変化す るので、 8倍波 (1 93 nm) ではその波長が 0. 0 1 25 nm変化し、 1 0 倍波 (1 57 nm) ではその波長が 0. 01 nm変化することになる。 Here, the oscillation wavelength of the DFB semiconductor laser 16 OA is about 0.1 nm / ° C. It has temperature dependence. Therefore, for example, if the temperature of the DFB semiconductor laser is changed by 1 ° C, the wavelength changes by 0.1 nm in the fundamental wave (1544 nm), and the wavelength changes in the eighth harmonic (193 nm). The wavelength changes by 0.0125 nm, and the wavelength changes by 0.01 nm at the 10th harmonic (157 nm).
なお、 露光装置では露光用照明光 (パルス光) の波長をその中心波長に対し て ± 20 pm程度変化させることができれば十分である。 従って、 D F B半導 体レーザ 1 60 Aの温度を 8倍波では ± 1. 6。C程度、 1 0倍波では ± 2°C程 度変化させれば良い。  In the exposure apparatus, it is sufficient if the wavelength of the exposure illumination light (pulse light) can be changed by about ± 20 pm with respect to the center wavelength. Therefore, the temperature of the DFB semiconductor laser 160 A is ± 1.6 at the eighth harmonic. In the case of C and 10th harmonic, it may be changed by about ± 2 ° C.
なお、 レーザ光源 1 60 Aとして、 D F B半導体レーザ等の半導体レーザに 限らず、 例えば発振波長が 990 n m付近のィッテルビウム(Y b) · ドープ · ファイバーレーザなどを用いることもできる。  The laser light source 160A is not limited to a semiconductor laser such as a DFB semiconductor laser, but may be a ytterbium (Yb) -doped fiber laser having an oscillation wavelength of around 990 nm, for example.
前記光カップラ B S 1、 B S 2としては、 透過率が 97%程度のものが用い られている。 このため、 D F B半導体レーザ 1 60 Aからのレーザ光は光カツ ブラ B S 1で分波され、 その 97%程度が次段の光カップラ B S 2に入射し、 残り 3%程度がビームモニタ機構 1 64に入射する。 また、 光カップラ B S 2 に入射したレーザ光は、 該光カップラ B S 2で分波され、 その 97%程度が次 段の光アイソレータ 1 60 Bに向かって進み、 残り 3%程度が吸収セル 1 65 に入射するようになっている。  As the optical couplers B S1 and B S2, those having a transmittance of about 97% are used. For this reason, the laser light from the DFB semiconductor laser 160 A is split by the optical coupler BS 1, and about 97% of the laser light is incident on the next-stage optical coupler BS 2, and the remaining about 3% is the beam monitor mechanism 164. Incident on. The laser light incident on the optical coupler BS 2 is demultiplexed by the optical coupler BS 2, and about 97% of the laser light travels toward the next-stage optical isolator 160 B, and the remaining about 3% is absorbed by the absorption cell 165. To be incident on.
なお、 ビームモニタ機構 1 64、 吸収セル 1 65等については、 後に更に詳 述する。  The beam monitor mechanism 164, absorption cell 165, etc. will be described later in further detail.
前記光アイソレータ 1 60 Bは、 光カップラ B S 2から EOM 1 60 Cに向 かう方向の光のみを通過させ、 反対向きの光の通過を阻止するためのデバイス である。 この光アイソレータ 1 60 Bにより、 反射光 (戻り光) に起因する D F B半導体レーザ 1 60 Aの発振モードの変化や雑音の発生等が防止される。 前記 EOM 1 60 Cは、 光アイソレータ 1 60 Bを通過したレーザ光 (CW 光(連続光))をパルス光に変換するためのものである。 EOM 1 60 Cとして は、 屈折率の時間変化に伴うチヤープによる半導体レーザ出力の波長広がりが 小さくなるように、 チヤープ補正を行った電極構造を持つ電気光学変調器 (例 えば二電極型変調器) が用いられている。 EOM 1 60 Cは、 光量制御装置 1 6 Cから印加される電圧パルスに同期して変調されたパルス光を出力する。 一 例として、 EOM 1 60 Cにより D F B半導体レーザ 1 6 OAで発振されたレ 一ザ光がパルス幅 1 n s、 繰り返し周波数 1 00 k H z (パルス周期約 1 0 s) のパルス光に変調されるものとすると、 この光変調の結果、 EOM 1 60 Cから出力されるパルス光のピーク出力は 2 OmW、平均出力は 2 となる。 なお、 ここでは、 EOM 1 60 Cの挿入による損失がないものとしたが、 その 挿入損失がある、 例えば損失が一 3 d Bである場合、 パルス光のピーク出力は 1 OmW、 平均出力は 1 Wとなる。 The optical isolator 160B is a device for passing only light in the direction from the optical coupler BS2 to the EOM 160C and blocking the light in the opposite direction. The optical isolator 160B prevents a change in the oscillation mode of the DFB semiconductor laser 160A and the generation of noise due to the reflected light (return light). The EOM 160C is for converting laser light (CW light (continuous light)) that has passed through the optical isolator 160B into pulsed light. EOM 1 as 60 C An electro-optic modulator (for example, a two-electrode type modulator) having an electrode structure with a chirp correction is used so that the wavelength spread of the semiconductor laser output due to the chirp due to the time change of the refractive index is reduced. . The EOM 160 C outputs a pulse light modulated in synchronization with a voltage pulse applied from the light amount control device 16 C. As an example, the laser light oscillated by the DFB semiconductor laser 16 OA by the EOM 160 C is modulated into pulse light with a pulse width of 1 ns and a repetition frequency of 100 kHz (pulse period of about 10 s). As a result, as a result of this optical modulation, the peak output of the pulse light output from the EOM 160 C is 2 OmW, and the average output is 2. Here, it is assumed that there is no loss due to the insertion of EOM 160 C. However, if the insertion loss is present, for example, if the loss is 13 dB, the peak output of the pulsed light is 1 OmW and the average output is 1 OmW. W.
なお、 繰り返し周波数を 1 00 k H z程度以上に設定した場合には、 後述す るファイバ増幅器において A S E (Amplified Spontaneous Emission,自然放出 光) ノイズの影響による増幅率低下を阻止することができるので、 このように することが望ましい。  When the repetition frequency is set to about 100 kHz or higher, a decrease in the amplification factor due to the influence of ASE (Amplified Spontaneous Emission) noise can be prevented in the fiber amplifier described later. This is desirable.
なお、 EOM 1 60 Cのみを用いてパルス光をオフの状態にしてもその消光 比が充分でない場合には、 D F B半導体レーザ 1 60 Aの電流制御を併用する ことが望ましい。すなわち、半導体レーザなどではその電流制御を行うことで、 出力光をパルス発振させることができるので、 D F B半導体レーザ 1 60Aの 電流制御と EOM 1 60 Cとを併用してパルス光を発生させることが望ましい c 一例として、 D F B半導体レーザ 1 60Aの電流制御によって、 例えば 1 0~ 20 n s程度のパルス幅を有するパルス光を発振させるとともに、 EOM 1 6 0 Cによってそのパルス光からその一部のみを切り出し、 パルス幅が 1 n sの パルス光に変調する。 このようにすれば、 EOM 1 60 Cのみを用いる場合に 比べて、 パルス幅が狭いパルス光を容易に発生させることが可能になるととも に、 パルス光の発振間隔や発振の開始及びその停止などをより簡単に制御する ことが可能になる。 If the extinction ratio is not sufficient even when the pulse light is turned off using only the EOM 160 C, it is desirable to use the current control of the DFB semiconductor laser 160 A together. That is, in a semiconductor laser or the like, the output light can be pulse-oscillated by controlling the current.Therefore, the pulse light can be generated by using the current control of the DFB semiconductor laser 160A and the EOM 160C together. As an example of a desirable c , a pulse light having a pulse width of, for example, about 10 to 20 ns is oscillated by current control of the DFB semiconductor laser 160A, and only a part of the pulse light is cut out from the pulse light by the EOM 160C. The pulse width is modulated to 1 ns. This makes it possible to easily generate pulsed light with a narrower pulse width than when only EOM 160 C is used, and to make it easier to generate pulsed light at intervals such as pulse light oscillation intervals and the start and stop of oscillation. Control more easily It becomes possible.
なお、 EOM 1 60 Cに代えて、 音響光学光変調素子 (AOM) を用いるこ とも可能である。  Note that an acousto-optic light modulator (AOM) can be used instead of the EOM 160C.
前記光増幅部 1 6 1は、 EOM 1 60 Cからのパルス光を増幅するもので、 ここでは、 複数のファイバ増幅器を含んで構成されている。 図 3には、 この光 増幅部 1 6 1の構成の一例が、 EON/M 60Cとともに示されている。  The optical amplifying unit 161 amplifies the pulse light from the EOM 160 C, and here includes a plurality of fiber amplifiers. FIG. 3 shows an example of the configuration of the optical amplifier 161, together with the EON / M 60C.
この図 3に示されるように、 光増幅部 1 6 1は、 チャネル 0からチャネル 1 2 7の総計 1 28チャネルを有する分岐及び遅延部 1 67と、 この分岐及び遅 延部 1 67のチャネル 0からチャネル 1 27の総計 1 28チャネルのそれぞれ の出力段に接続されたファイバ増幅器 1 68,〜1 68128と、これらのファイバ 増幅器 1 68,〜1 68128のそれぞれに狭帯域フィルタ 1 69,〜1 6 9128及び 光アイソレータ 1 70,〜1 70128をそれぞれ介して接続された最終段のファ ィバ増幅器 1 7 1 ,〜·! 7 1128等を備えている。 この場合、 図 3からも明らかな ように、 ファイバ増幅器 1 68n、 狭帯域化フィルタ 1 69n、 光アイソレータ 1 70n、 及びファイバ増幅器 1 7 1 n (n = 1、 2、 ……、 1 28) によって、 それぞれ光経路 1 72π (n = l、 2、 ……、 1 28) が構成されている。 光増幅部 1 6 1の上記構成各部について更に詳述すると、 前記分岐及び遅延 部 1 6 7は、 総計 1 28チャネルのチャネルを有し、 各チャネルの出力に所定 の遅延時間 (ここでは、 3 n s) を与えるためのものである。 As shown in FIG. 3, the optical amplifying unit 161 includes a branch and delay unit 167 having a total of 128 channels from channel 0 to channel 127, and a channel 0 of the branch and delay unit 167. channel 1 27 total 1 28 channel of the respective output stage connected fiber amplifiers 1 68 from ~ 1 68 128, these fiber amplifiers 1 68, and 1 68 narrowband filter 1 69 to each of 128 ~ 1 6 9 128 and the optical isolator 1 70, and 1 70 128 in the final stage which is connected via respective file I bus amplifier 1 7 1 ~ -! 7 1 128 etc. In this case, as is clear from FIG. 3, the fiber amplifier 168 n , the narrow-band filter 169 n , the optical isolator 170 n , and the fiber amplifier 171 n (n = 1, 2, ……, 1 28), optical paths 1 72 π (n = 1, 2,…, 1 28) are respectively formed. The above-described components of the optical amplification unit 161 will be described in more detail. The branching and delay unit 167 has a total of 128 channels, and outputs a predetermined delay time (here, 3 ns).
この分岐及び遅延部 1 67は、 本実施形態では、 EOM 1 60 Cから出力さ れるパルス光を 35 d B (3 1 62倍)の光増幅を行うエルビウム (E r) · ド 一プ 'ファイバ増幅器 (E D FA) と、 この E D F Aの出力をチャネル 0~3 の 4出力に並列分割する光分岐装置であるスプリツタ (平板導波路 1 X4スプ リツ夕) と、 このスプリツ夕のチャネル 0〜3の各出力端に接続された各々長 さの異なる 4本の光ファイバと、 これら 4本の光ファイバの出力をそれぞれチ ャネル 0〜3 1に 32分割する 4つのスプリツタ (平板導波路 1 X32スプリ ッタ) と、 各スプリツ夕のチャネル 0を除くチャネル 1 ~3 1にそれぞれ接続 された長さの異なる各 3 1本 (総計 1 24本) の光ファイバとを含んで構成さ れている。 以下、 上記各スプリツ夕 (平板導波路 1 X 32スプリツ夕) の 0~ 3 1チャネルを総称してブロックと呼ぶ。 In this embodiment, the branching and delay unit 167 is an erbium (Er) -doped fiber for amplifying the pulse light output from the EOM 160 C by 35 dB (3162 times). An amplifier (EDFA), a splitter (a flat waveguide 1 X4 splitter), which is an optical splitter that splits the output of the EDFA into four outputs of channels 0 to 3 in parallel, and channels 0 to 3 of the splitter Four optical fibers with different lengths connected to each output end, and four splitters that divide the output of these four optical fibers into channels 0 to 31 respectively (32 planar waveguides 1x32 splitter) ) And 31 optical fibers (total of 124) of different lengths connected to channels 1 to 31 except for channel 0 of each splitter. Hereinafter, the 0 to 31 channels of each of the above splitters (flat waveguide 1 × 32 splitter) will be collectively called a block.
これを更に詳述すると、 上記初段の E D F Aから出力されるパルス光は、 ピ ーク出力約 63 W、 平均出力約 6. 3mWとなる。 このパルス光がスプリツ夕 (平板導波路 1 X 4スプリツタ) によりチャネル 0~3の 4出力に並列分割さ れ、 各チャネルの出力光には、 上記 4本の光ファイバ長に対応した遅延が与え られる。例えば本実施形態では、 光ファイバ中の光の伝搬速度を 2 X 1 08m - sであるとし、 スプリッタ (平板導波路 1 X 4スプリツ夕) のチャネル 0、 1、 2、 3にそれぞれ 0. 1 m、 1 9. 3 m、 38. 5 m、 57. 7 mの長さの光 ファイバ (以下、 「第 1の遅延ファイバ」 と呼ぶ) が接続されている。 More specifically, the pulse light output from the first-stage EDFA has a peak output of about 63 W and an average output of about 6.3 mW. This pulse light is split in parallel into four outputs of channels 0 to 3 by a splitter (a flat waveguide 1 × 4 splitter), and the output light of each channel is given a delay corresponding to the above four optical fiber lengths. Can be For example, in this embodiment, the propagation speed of light in the optical fiber 2 X 1 0 8 m - and is s, respectively for channel 0, 1, 2, 3 of the splitter (flat plate waveguide 1 X 4 Supuritsu evening) 0 1 m, 19.3 m, 38.5 m, and 57.7 m lengths of optical fiber (hereinafter referred to as “first delay fiber”) are connected.
この場合、 各第 1の遅延ファイバ出口での隣り合うチャネル間の光の遅延は 9 6 n sとなる。 In this case, the optical delay between adjacent channels at each first delay fiber exit is 96 ns.
また、 上記 4つのスプリツ夕 (平板導波路 1 X 32スプリッタ) のチャネル 1〜3 1には、 それぞれ 0. 6 XNメー卜ル (Nはチャネル番号) の長さの光 ファイバ (以下、 「第 2の遅延ファイバ」 と呼ぶ)が接続されている。 この結果、 各ブロック内の隣り合うチャネル間では 3 n sの遅延が与えられ、 各ブロック のチャネル 0出力に対し、 チャネル 3 1出力は、 3 X 3 1 =93 n sの遅延が 与えられる。  In addition, channels 1 to 31 of the four splitters (flat waveguide 1 × 32 splitter) each have an optical fiber of 0.6 XN meter (where N is the channel number) (hereinafter referred to as “No. 2 called "delay fiber"). As a result, a delay of 3 ns is given between adjacent channels in each block, and a delay of 3 × 31 = 93 ns is given to the output of channel 31 with respect to the output of channel 0 of each block.
一方、 第 1から第 4までの各ブロック間には、 前記のように第 1の遅延ファ ィバによって、各プロックの入力時点で各々 96 n sの遅延が与えられている。 従って、 第 2ブロックのチャネル 0出力は第 1プロックのチャネル 0出力に対 し 96 n sの遅延となり、 第 1ブロックのチャネル 31との遅延は 3 n sとな る。 このことは、第 2〜第 3、第 3〜第 4のプロック間においても同様である。 この結果、 全体の出力として総計 1 28チャネルの出力端で、 隣り合うチヤネ ル間に 3 n sの遅延を持つパルス光が得られる。 On the other hand, a delay of 96 ns is given between the first to fourth blocks by the first delay fiber at the time of input of each block as described above. Therefore, the channel 0 output of the second block has a delay of 96 ns with respect to the channel 0 output of the first block, and the delay with the channel 31 of the first block is 3 ns. This is the same between the second and third blocks and the third and fourth blocks. As a result, a total of 128 channels of output ends, adjacent channels A pulse light with a delay of 3 ns between the pulses is obtained.
以上の分岐及び遅延により、 総計 1 28チャネルの出力端では、 隣り合うチ ャネル間で 3 n sの遅延を持つパルス光が得られるが、 このとき各々の出力端 で観測される光パルスは、 EOM 1 60 Cによって変調されたパルスと同じ 1 00 k H z (パルス周期 1 O ^ s) である。 従って、 レーザ光発生部全体とし て見ると、 1 28パルスが 3 n s間隔で発生した後、 9. 62 sの間隔を置 いて次のパルス列が発生するという繰り返しが 1 00 k H zで行われる。 即ち 全体の出力は 1 28X 1 00 X 1 03= 1. 28 X 1 07パルス 秒となる。 なお、 本実施形態では、 分割数を 1 28とし、 また遅延用ファイバとして短 いものを用いた例について説明した。 このため各パルス列の間に 9. 62 M S の発光しない間隔が生じたが、 分割数を増加させる、 または遅延用ファイバを より長くして適切な長さとする、 あるいはこれらを組み合わせて用いることに より、 パルス間隔を完全な等間隔とすることも可能である。 By the above branching and delay, a pulse light with a delay of 3 ns is obtained between adjacent channels at the output terminals of a total of 128 channels.At this time, the optical pulse observed at each output terminal is EOM It is the same 100 kHz (pulse period 1 O ^ s) as the pulse modulated by 160 C. Therefore, as a whole, the laser beam generator repeats at 128 kHz, with 128 pulses generated at 3 ns intervals and the next pulse train generated at 9.62 s intervals. . That the entire output becomes 1 28X 1 00 X 1 0 3 = 1. 28 X 1 0 7 pulses seconds. In this embodiment, an example has been described in which the number of divisions is set to 128 and a short fiber is used as the delay fiber. This resulted in a 9.62 MS non-emission interval between each pulse train, but by increasing the number of divisions, lengthening the delay fiber to an appropriate length, or using a combination of these It is also possible to make the pulse intervals completely equal.
前記ファイバ増幅器 1 68n (n = 1、 2、 ……、 1 28) としては、 ここで は、 通常通信で用いられているものと同様に光ファイバのモードフィールド径 (以下 「モード径 J という) が 5〜6 mのエルビウム (E r) · ドープ'ファ ィバ増幅器(EDFA)が用いられている。 このファイバ増幅器 1 68nによつ て、 遅延部 1 67の各チャネルからの出力光が、 所定の増幅利得に応じて増幅 される。なお、 このファイバ増幅器 1 68nの励起光源等については後述する。 前記狭帯域フィルタ 1 69n (n = 1、 2、 ……、 1 28) は、 ファイバ増幅 器 1 68nで発生する A S E光をカツ卜し、かつ D F B半導体レーザ 1 6 OAの 出力波長 (波長幅は 1 pm程度以下) を透過させることで、 透過光の波長幅を 実質的に狭帯化するものである。 これにより、 AS E光が後段のファイバ増幅 器 1 7 1 nに入射してレーザ光の増幅利得を低下させるのを防止し、あるいは A S Eノイズの伝播によるレーザ光の散乱を防止することができる。 ここで、 狭 帯域フィルタ 1 69„はその透過波長幅が 1 pm程度であることが好ましいが、 A S E光の波長幅は数十 n m程度であるので、 現時点で得られる透過波長幅が 1 00 pm程度の狭帯域フィルタを用いても実用上問題がない程度に AS E光 をカツ卜することができる。 As the fiber amplifier 168 n (n = 1, 2,..., 128), the mode field diameter of the optical fiber (hereinafter referred to as “mode diameter J”) is the same as that used in normal communication. Erbium (Er) -doped fiber amplifier (EDFA) with a length of 5 to 6 m.The output light from each channel of the delay unit 167 is provided by the fiber amplifier 168 n . Is amplified according to a predetermined amplification gain.The excitation light source of the fiber amplifier 168 n will be described later.The narrow band filter 169 n (n = 1, 2,..., 128) Is to cut the ASE light generated by the fiber amplifier 168 n and transmit the output wavelength of the DFB semiconductor laser 16 OA (wavelength width is about 1 pm or less) to substantially reduce the wavelength width of the transmitted light. As a result, the ASE light is converted to the fiber amplifier 17 1 n in the subsequent stage. In this case, it is possible to prevent the amplification gain of the laser light from being lowered by being incident on the laser beam, or to prevent the scattering of the laser light due to the propagation of the ASE noise. It is preferably about pm, Since the wavelength width of the ASE light is about several tens of nm, it is possible to cut the ASE light so that there is no practical problem even if a narrow band filter with a transmission wavelength width of about 100 pm is available at this time. it can.
また、 本実施形態では、 後述するように D F B半導体レーザ 1 6 OAの出力 波長を積極的に変化させることがあるので、 その出力波長の可変幅 (本実施形 態の露光装置では一例として ± 20 pm程度) に応じた透過波長幅 (可変幅と 同程度以上) を持つ狭帯域フィルタを用いておくことが好ましい。 なお、 露光 装置に適用されるレーザ装置ではその波長幅が 1 p m程度以下に設定される。 前記光アイソレータ 1 70n (n = 1、 2、 ……、 1 28) は、 先に説明した 光アイソレータ 1 6 0 Bと同様に、戻り光の影響を低減するためのものである。 前記ファイバ増幅器 1 7 1 π (n = 1、 2、 ……、 1 28) としては、 ここで は、 光ファイバ中での非線形効果による増幅光のスぺク卜ル幅の増加を避ける ため光ファイバのモード径が通常通信で用いられているもの (5〜6 Atm) よ りも広い、 例えば 20~30 mの大モード径の E D F Aが用いられている。 このファイバ増幅器 1 7 1 nは、 前述したファイバ増幅器 1 68„で増幅された 分岐及び遅延部 1 6 7の各チャネルからの光出力を更に増幅する。一例として、 分岐及び遅延部 1 6 7での各チャネルの平均出力約 5 0 W、 全チャネルでの 平均出力約 6. 3mWを 2段のファイバ増幅器 1 68„、 1 7 によつて合計 46 d B (40600倍) の増幅を行うものとすると、 各チャネルに対応する 光経路 1 72nの出力端 (ファイバ増幅器 1 7 1 nを構成する光ファイバの出力 端) では、 ピーク出力 20 k W、 パルス幅 1 n s、 パルス繰り返し周波数 1 0 O k H z、 平均出力 2W、 全チャネルでの平均出力 256 Wを得る。 なお、 こ のファイバ増幅器 1 7 の励起光源等についても後述する。 Further, in the present embodiment, the output wavelength of the DFB semiconductor laser 16 OA may be actively changed as described later. It is preferable to use a narrow-band filter having a transmission wavelength width (approximately equal to or greater than the variable width) according to (approximately pm). The wavelength width of a laser device applied to an exposure device is set to about 1 pm or less. The optical isolator 170 n (n = 1, 2,..., 128) is for reducing the effect of return light, similarly to the optical isolator 160 B described above. Said fiber amplifier 1 7 1 π (n = 1 , 2, ......, 1 28) as here, the light in order to avoid an increase in Supekubokuru width of amplified light due to the nonlinear effect in the optical fiber EDFAs with a large mode diameter, for example, 20 to 30 m, are used, which have fiber mode diameters wider than those used in normal communication (5 to 6 Atm). The fiber amplifier 171 n further amplifies the optical output from each channel of the branch and delay unit 167 amplified by the above-described fiber amplifier 168. As an example, the branch and delay unit 167 The average output of each channel is about 50 W, and the average output of all channels is about 6.3 mW, which is amplified by a total of 46 dB (40600 times) by two-stage fiber amplifiers 168 „and 17. Then, at the output end of the optical path 172 n corresponding to each channel (the output end of the optical fiber constituting the fiber amplifier 171 n ), the peak output is 20 kW, the pulse width is 1 ns, and the pulse repetition frequency is 10 O Obtain 2 kHz, 2 W average power, and 256 W average power on all channels. The pump light source of the fiber amplifier 17 will be described later.
本実施形態では、 分岐及び遅延部 1 67での各チャネルに対応する光経路 1 72nの出力端、 すなわちファイバ増幅器 1 7 1 nを構成する各光ファイバの出 力端は、 バンドル状に束ねられ、 図 4に示されるような断面形状を有するバン ドル一ファイバ 1 7 3が形成されている。 このとき、 各光ファイバのクラッド 直径は 1 2 5 Ai m程度であることから、 1 2 8本を束ねた出力端でのバンドル の直径は約 2 m m以下とすることができる。 本実施形態では、 バンドルーファ ィバ 1 7 3は最終段のファイバ増幅器 1 7 1„の出力端をそのまま用いて形成 しているが、最終段のファイバ増幅器 1 7 1 πに無ドープの光ファイバを結合さ せ、 その出力端でバンドル一ファイバを形成することも可能である。 In the present embodiment, Chikaratan out of the optical fibers constituting the output end of the optical path 1 72 n corresponding to each channel at the branch and delay unit 1 67, i.e. the fiber amplifier 1 7 1 n is bundled in a bundle shape And have a cross section as shown in Fig. 4. A dollar fiber 1 173 is formed. At this time, since the clad diameter of each optical fiber is about 125 Aim, the diameter of the bundle at the output end of the bundle of 128 fibers can be made about 2 mm or less. In this embodiment, the bundle fiber 173 is formed using the output end of the final stage fiber amplifier 171 „as it is, but the undoped optical fiber is added to the final stage fiber amplifier 171π. Can be combined to form a bundle-one fiber at its output end.
なお、標準的なモード径を持つ前段のファイバ増幅器 1 6 8 ηと、上記モード 径の広い最終段のファイバ増幅器 1 7 1 ηとの接続は、テーパ状にモード径が增 加する光ファイバを用いて行われている。 Note that the previous stage of the fiber amplifier 1 6 8 eta with standard mode diameter, connected to the fiber amplifier 1 7 1 eta wide final stage of the mode diameter, the optical fiber the mode diameter in a tapered shape is pressurized增It is performed using.
次に、 図 5に基づいて各ファイバ増幅器の励起用光源等について説明する。 図 5には、 光増幅部 1 6 1を構成するファイバ増幅器及びその周辺部が、 波長 変換部 1 6 3の一部とともに概略的に示されている。  Next, the excitation light source and the like of each fiber amplifier will be described with reference to FIG. FIG. 5 schematically shows a fiber amplifier constituting the optical amplifying unit 161 and a peripheral portion thereof, together with a part of the wavelength converting unit 163.
この図 5において、第 1段のファイバ増幅器 1 6 8 ηにはその励起用の半導体 レーザ 1 7 8がファイバ結合されるとともに、 この半導体レーザ 1 7 8の出力 が波長分割多重化装置 (Wave l ength Divi s ion Mu l t ip lexer : W D M ) 1 7 9を 通してフアイバ増幅器用ドープ ·フアイバに入力し、 それによりこのドープ · ファイバが励起されるようになっている。 In FIG. 5, a semiconductor laser 178 for pumping the first stage fiber amplifier 168 η is fiber-coupled to the fiber amplifier 168 η, and the output of the semiconductor laser 178 is coupled to a wavelength division multiplexing device (Wavel The signal is input to a fiber amplifier dope fiber through an intensity division multiplexer (WDM) 179 to excite the doped fiber.
一方大モード径をもつファイバ増幅器 1 7 1 nでは、上記のモード径の大きい ファイバ増幅器用ドープ ·ファイバを励起するための励起用光源としての半導 体レーザ 1 7 4を、 ファイバ増幅器用ドープ,ファイバの径に合わせた大モー ド径ファイバにファイバ結合し、 この半導体レーザ 1 7 4の出カを 0 1^1 1 7 6を用いて、 光増幅器用ドープ*ファイバに入力し、 ドープ ·ファイバを励起 する。 On the other hand, the fiber amplifier 17 1 n having a large mode diameter uses a semiconductor laser 17 4 as a pumping light source for pumping the above-described fiber amplifier dope having a large mode diameter, and a fiber amplifier dope. The fiber is coupled to a large-diameter fiber that matches the diameter of the fiber, and the output of this semiconductor laser 174 is input to a doped * fiber for optical amplifier using 0 1 ^ 1 176, and the doped fiber To excite.
この大モード径ファイバ(ファイバ増幅器) 1 7 1„で増幅されたレーザ光は 波長変換部 1 6 3に入射し、 ここで紫外レーザ光に波長変換される。 なお、 こ の波長変換部 1 6 3の構成等については後述する。 大モード径ファイバ(ファイバ増幅器) 1 7 1 nを伝播する増幅されるべきレ 一ザ光 (信号) は、 主に基本モードであることが望ましく、 これは、 シングル モードあるいはモード次数の低いマルチモードファイバにおいて、 主に基本モ 一ドを選択的に励起することにより実現できる。 The laser light amplified by the large-mode diameter fiber (fiber amplifier) 17 1 „enters the wavelength conversion section 16 3, where it is converted into an ultraviolet laser light. Configuration 3 and the like will be described later. Large mode diameter fibers (fiber amplifier) 1 7 1 n les to be amplified propagating Ichizako (signal) is desirably mainly the fundamental mode, which is single-mode or mode order lower multimode In a fiber, this can be mainly achieved by selectively exciting the basic mode.
本実施形態では、 大モード径ファイバに結合された高出力半導体レーザを、 前方向から 4個及び後方向から 4個ファイバ結合している。 ここで、 励起用半 導体レーザ光を効率良く光増幅用ドープ,ファイバに結合するためには、 光増 幅用ドープ ·ファイバとして、 クラッドが 2重構造となったダブルクラッド構 造の光ファイバを用いることが望ましい。このとき、励起用半導体レーザ光は、 W D M 1 7 6により、 ダブルクラッドの内側クラッドに導入される。  In the present embodiment, four high-power semiconductor lasers coupled to a large-mode diameter fiber are fiber-coupled from the front and four from the rear. Here, in order to efficiently couple the pumping semiconductor laser light to the optical amplification dope / fiber, an optical fiber having a double clad structure with a double clad structure is used as the optical amplification dope fiber. It is desirable to use. At this time, the pumping semiconductor laser light is introduced into the inner clad of the double clad by WDM176.
前記半導体レーザ 1 7 8、 1 7 4は、 光量制御装置 1 6 Cによって制御され るようになっている。  The semiconductor lasers 178 and 174 are controlled by a light amount control device 16C.
また、本実施形態では、前述した光経路 1 7 2 nを構成する光ファイバとして ファイバ増幅器 1 6 8 n、 1 7 1„が設けられているため、 各ファイバ増幅器の ゲインの差が各チャネルの光出力のばらつきとなる。 このため、 本実施形態で は、 各チャネルのファイバ増幅器 (1 6 8 n、 1 7 1 n) で出力の一部が分岐さ れ、 それぞれの分岐端に設けられた光電変換素子 1 8 0、 1 8 1によってそれ ぞれ光電変換されるようになっている。 これらの光電変換素子 1 8 0、 1 8 1 の出力信号が光量制御装置 1 6 Cに供給されるようになっている。 Further, in the present embodiment, since the fiber amplifier 1 6 8 n, 1 7 1 " is provided as the optical fiber constituting the optical path 1 7 2 n described above, the difference between the gain of each fiber amplifier in each channel the variation of the optical output. Thus, in this embodiment, a portion of output fiber amplifier of each channel (1 6 8 n, 1 7 1 n) is branched, provided each branch ends The photoelectric conversion is performed by the photoelectric conversion elements 180 and 181, respectively.The output signals of these photoelectric conversion elements 180 and 181 are supplied to the light quantity control device 16C. It has become.
光量制御装置 1 6 Cでは、 各ファイバ増幅器からの光出力が各増幅段で一定 になるように (即ちバランスするように)、 各励起用半導体レーザ(1 7 8、 1 7 4 ) のドライブ電流をフィードバック制御するようになっている。  In the light amount control device 16C, the drive current of each pumping semiconductor laser (178, 174) is controlled so that the optical output from each fiber amplifier is constant (that is, balanced) in each amplification stage. Feedback control.
さらに、 本実施形態では、 図 5に示されるように、 波長変換部 1 6 3の途中 でビームスプリッタにより分岐された光が光電変換素子 1 8 2によつて光電変 換され、 該光電変換素子 1 8 2の出力信号が光量制御装置 1 6 Cに供給される ようになつている。 光量制御装置 1 6 Cでは、 この光電変換素子 1 8 2の出力 信号に基づいて波長変換部 1 6 3における光強度をモニタし、 波長変換部 1 6 3からの光出力が所定の光出力となるように、 励起用半導体レーザ 1 7 8、 1 7 4の少なくとも一方のドライブ電流をフィードバック制御する。 Further, in the present embodiment, as shown in FIG. 5, the light split by the beam splitter in the middle of the wavelength conversion section 163 is photoelectrically converted by the photoelectric conversion element 182, and the photoelectric conversion element The output signal of 18 2 is supplied to the light quantity control device 16 C. In the light quantity control device 16 C, the output of this photoelectric conversion element 18 2 The light intensity in the wavelength conversion unit 163 is monitored based on the signal, and at least one of the pumping semiconductor lasers 178 and 174 is controlled so that the light output from the wavelength conversion unit 163 becomes a predetermined light output. One drive current is feedback-controlled.
このような構成とすることにより、 各増幅段毎に各チャネルのファイバ増幅 器の増幅率が一定化されるため、 各ファイバ増幅器間に偏った負荷がかかるこ とがなく全体として均一な光強度が得られる。 また、 波長変換部 1 6 3におけ る光強度をモニタすることにより、 予定される所定の光強度を各増幅段にフィ ードバックし、 所望の紫外光出力を安定して得ることができる。  With such a configuration, the amplification factor of the fiber amplifier of each channel is fixed at each amplification stage, so that there is no uneven load between the fiber amplifiers and the light intensity is uniform as a whole. Is obtained. In addition, by monitoring the light intensity in the wavelength converter 163, a predetermined light intensity is fed back to each amplification stage, and a desired ultraviolet light output can be stably obtained.
なお、 光量制御装置 1 6 Cについては、 後に更に詳述する。  The light amount control device 16C will be described later in further detail.
上述のようにして構成された光増幅部 1 6 1 (バンドル一ファイバ 1 7 3を 形成する各光ファイバ出力端) からは、 偏光調整装置 1 6 Dによって後述する ようにしてパルス光がすべて円偏光に揃えられて出力される。 これら円偏光で あるパルス光は、 四分の一波長板 1 6 2 (図 2参照) によって、 すべて偏光方 向が同一方向となる直線偏光に変換され、次段の波長変換部 1 6 3に入射する。 前記波長変換部 1 6 3は、 複数の非線形光学結晶を含み、 前記増幅されたパ ルス光 (波長 1 . 5 4 4 μ πΐの光) をその 8倍高調波又は 1 0倍高調波に波長 変換して、 A r Fエキシマレーザと同じ出力波長 (1 9 3 n m ) あるいは F 2 レーザと同じ出力波長 (1 5 7 n m) のパルス紫外光を発生する。 From the optical amplifying unit 16 1 (the output end of each optical fiber forming the bundle-to-fiber 1773) configured as described above, all the pulsed light is circularized by the polarization adjusting device 16 D as described later. The output is aligned with the polarized light. These circularly polarized pulse lights are converted by the quarter-wave plate 162 (see Fig. 2) into linearly polarized lights, all of which have the same polarization direction. Incident. The wavelength conversion section 163 includes a plurality of nonlinear optical crystals, and converts the amplified pulse light (light having a wavelength of 1.544 μπ μ) into an 8th harmonic or a 10th harmonic thereof. conversion to, for generating a pulse ultraviolet light a r F excimer laser with the same output wavelength (1 9 3 nm) or an F 2 laser with the same output wavelength (1 5 7 nm).
図 6 A、 図 6 Bには、 この波長変換部 1 6 3の構成例が示されている。 ここ で、 これらの図に基づいて波長変換部 1 6 3の具体例について説明する。  FIG. 6A and FIG. 6B show a configuration example of the wavelength conversion unit 163. Here, a specific example of the wavelength converter 163 will be described based on these drawings.
図 6 Aは、 バンドル—ファイバ 1 7 3の出力端から射出される波長 1 . 5 4 4 x mの基本波を、非線形光学結晶を用いて 8倍波(高調波) に波長変換して、 A r Fエキシマレーザと同じ波長である 1 9 3 n mの紫外光を発生する構成例 を示す。 また、 図 6 Bは、 バンドル一ファイバ 1 7 3の出力端から射出される 波長 1 . 5 7 mの基本波を非線形光学結晶を用いて 1 0倍波の高調波発生を 行い、 F 2レーザと同じ波長である 1 5 7 n mの紫外光を発生する構成例を示す。 図 6 Aの波長変換部では、 基本波 (波長 1. 544 ΜΓΤΙ) → 2倍波 (波長 7 72 nm) → 3倍波 (波長 5 1 5 n m) → 4倍波 (波長 386 n m) → 7倍波 (波長 22 1 nm) →8倍波 (波長 1 93 n m) の順に波長変換が行われる。 これを更に詳述すると、 バンドル一ファイバ 1 73の出力端から出力される 波長 1 . 544 m (周波数 ω) の基本波は、 1段目の非線形光学結晶 533 に入射する。 基本波がこの非線形光学結晶 533を通る際に、 2次高調波発生 により基本波の周波数 ωの 2倍、 すなわち周波数 2ω (波長は1 2の772 nm) の 2倍波が発生する。 なお、 図 6 Aの場合には、 上述の四分の一波長板 1 62による直線偏光化は、 非線形光学結晶 533において 2倍波が最も効率 良く発生する偏光方向となるように行われる。 かかる直線偏光の偏光方向の設 定は、四分の一波長板 1 62の光学軸の方向を調整することによって行われる。 この 1段目の非線形光学結晶 533として、 L i B305 (L BO) 結晶が用 いられ、 基本波を 2倍波に波長変換するための位相整合に L BO結晶の温度調 節による方法、 NC PM (Non-Critical Phase Matching) が使用される。 NC PMは、 非線形光学結晶内での基本波と第二高調波との角度ずれ (Walk- of が 起こらないため高効率で 2倍波への変換を可能にし、 また発生した 2倍波は Walk-off によるビームの変形も受けないため有利である。 Figure 6A shows a bundle—a 1.54 4 xm fundamental wave emitted from the output end of fiber 173 is converted to an 8th harmonic (harmonic) using a nonlinear optical crystal. An example of a configuration that generates 193 nm ultraviolet light, which is the same wavelength as the rF excimer laser, is shown. Also, FIG. 6 B performs harmonic generation 1 0 harmonic by using a nonlinear optical crystal a fundamental wave having a wavelength 1. 5 7 m emitted from the output end of the bundle one fiber 1 7 3, F 2 laser An example of a configuration for generating an ultraviolet light having a wavelength of 157 nm, which is the same wavelength as that of FIG. In the wavelength converter shown in Fig. 6A, the fundamental wave (wavelength 1.544 mm) → the second harmonic wave (wavelength 772 nm) → the third harmonic wave (wavelength 5 15 nm) → the fourth harmonic wave (wavelength 386 nm) → 7 Wavelength conversion is performed in the order of harmonic (wavelength 221 nm) → eighth harmonic (wavelength 193 nm). More specifically, the fundamental wave having a wavelength of 1.544 m (frequency ω) output from the output end of the bundle-one fiber 173 enters the first-stage nonlinear optical crystal 533. When the fundamental wave passes through the nonlinear optical crystal 533, a second harmonic is generated, which is twice the frequency ω of the fundamental wave, that is, a second harmonic having a frequency 2ω (wavelength is 12 = 772 nm). In the case of FIG. 6A, the above-described linear polarization by the quarter-wave plate 162 is performed so that the nonlinear optical crystal 533 has a polarization direction in which the second harmonic is generated most efficiently. The setting of the polarization direction of such linearly polarized light is performed by adjusting the direction of the optical axis of the quarter-wave plate 162. As the nonlinear optical crystal 533 in the first stage, L i B 3 0 5 ( L BO) Irare use crystals, according to the temperature regulatory of L BO crystal phase matching for wavelength conversion of the fundamental wave to the second harmonic wave Method, NC PM (Non-Critical Phase Matching) is used. The NC PM is capable of high-efficiency conversion to the second harmonic wave because no walk-of occurs between the fundamental wave and the second harmonic in the nonlinear optical crystal. This is advantageous because the beam is not deformed by -off.
非線形光学結晶 533で波長変換されずに透過した基本波と、 波長変換で発 生した 2倍波とは、 次段の波長板 534でそれぞれ半波長、 1波長の遅延が与 えられて、 基本波のみその偏光方向が 90度回転し、 2段目の非線形光学結晶 536に入射する。 2段目の非線形光学結晶 536として L B0結晶が用いら れるとともに、 その L BO結晶は 1段目の非線形光学結晶 (L B0結晶) 53 3とは温度が異なる NC PMで使用される。 この非線形光学結晶 536では、 1段目の非線形光学結晶 533で発生した 2倍波と、 波長変換されずにその非 線形光学結晶 533を透過した基本波とから和周波発生により 3倍波 (波長 5 1 5 n m) を得る。 次に、 非線形光学結晶 536で得られた 3倍波と、 波長変換されずにその非 線形光学結晶 536を透過した基本波および 2倍波とは、 ダイクロイツク ·ミ ラー 537により分離され、 ここで反射された 3倍波は集光レンズ 540、 及 びダイクロイツク ' ミラー 543を通って 4段目の非線形光学結晶 545に入 射する。 一方、 ダイクロイツク ·ミラー 537を透過した基本波および 2倍波 は、 集光レンズ 538を通って 3段目の非線形光学結晶 539に入射する。 The fundamental wave transmitted through the non-linear optical crystal 533 without wavelength conversion and the second harmonic generated by the wavelength conversion are delayed by a half-wavelength and a one-wavelength in the next-stage wave plate 534, respectively. Only the wave rotates its polarization direction by 90 degrees and enters the second-stage nonlinear optical crystal 536. An LBO crystal is used as the second-stage nonlinear optical crystal 536, and the LBO crystal is used in the NC PM having a temperature different from that of the first-stage nonlinear optical crystal (LB0 crystal) 533. In this nonlinear optical crystal 536, a third harmonic (wavelength) is generated by sum frequency generation from the second harmonic generated in the first-stage nonlinear optical crystal 533 and the fundamental wave transmitted through the nonlinear optical crystal 533 without wavelength conversion. 5 15 nm). Next, the third harmonic obtained by the nonlinear optical crystal 536 and the fundamental wave and the second harmonic transmitted through the nonlinear optical crystal 536 without wavelength conversion are separated by the dichroic mirror 537. The third harmonic reflected by the light passes through the condenser lens 540 and the dichroic mirror 543 and enters the fourth-stage nonlinear optical crystal 545. On the other hand, the fundamental wave and the second harmonic transmitted through the dichroic mirror 537 pass through the condenser lens 538 and enter the third-stage nonlinear optical crystal 539.
3段目の非線形光学結晶 539としては L BO結晶が用いられ、 基本波が波 長変換されずにその L BO結晶を透過するとともに、 2倍波が L BO結晶で 2 次高調波発生により 4倍波 (波長 386 nm) に変換される。 非線形光学結晶 539で得られた 4倍波とそれを透過した基本波とは、 ダイクロイツク ·ミラ -54 1 により分離され、 ここを透過した基本波は集光レンズ 544を通ると ともに、 ダイクロイツク · ミラー 546で反射されて 5段目の非線形光学結晶 548に入射する。 一方、 ダイクロイツク ·ミラー 54 1で反射された 4倍波 は、 集光レンズ 542を通ってダイクロイツク ·ミラー 543に達し、 ここで ダイクロイツク · ミラー 53 7で反射された 3倍波と同軸に合成されて 4段目 の非線形光学結晶 545に入射する。  As the third-stage nonlinear optical crystal 539, an LBO crystal is used. The fundamental wave passes through the LBO crystal without wavelength conversion, and the second harmonic is generated by the second harmonic generation in the LBO crystal. It is converted to a harmonic (wavelength 386 nm). The fourth harmonic obtained by the nonlinear optical crystal 539 and the fundamental wave transmitted therethrough are separated by the dichroic mirror -54 1, and the fundamental wave transmitted there passes through the condenser lens 544 and becomes dichroic · The light is reflected by the mirror 546 and enters the fifth-stage nonlinear optical crystal 548. On the other hand, the fourth harmonic reflected by the dichroic mirror 54 1 passes through the condenser lens 542 and reaches the dichroic mirror 543, where it is coaxial with the third harmonic reflected by the dichroic mirror 537. The synthesized light enters the fourth stage nonlinear optical crystal 545.
4段目の非線形光学結晶 545としては、 /3— B a B204 (B BO) 結晶が 用いられ、 3倍波と 4倍波とから和周波発生により 7倍波 (波長 22 1 nm) を得る。 非線形光学結晶 545で得られた 7倍波は集光レンズ 547を通ると ともに、 ダイクロイツク ' ミラー 546で、 ダイクロイツク ' ミラー 54 1を 透過した基本波と同軸に合成されて、 5段目の非線形光学結晶 548に入射す る。 The nonlinear optical crystal 545 in the fourth stage, / 3- B a B 2 0 4 (B BO) crystal is used, the third harmonic and 7 harmonic (wavelength 22 1 nm by sum frequency generation and a fourth harmonic ). The 7th harmonic obtained by the nonlinear optical crystal 545 passes through the condenser lens 547, and is coaxially synthesized with the fundamental wave transmitted through the dichroic mirror 541 by the dichroic mirror 546. The light enters the nonlinear optical crystal 548.
5段目の非線形光学結晶 548として L BO結晶が用いられ、 基本波と 7倍 波とから和周波発生により 8倍波 (波長 1 93 nm) を得る。 上記構成におい て、 7倍波発生用 B BO結晶 545、 及び 8倍波発生用 L BO結晶 548のか わりに、 C s L i B6O10 (C L BO) 結晶、 あるいは L i 2B407 (L B 4) 結 晶を用いることも可能である。 An LBO crystal is used as the fifth-stage nonlinear optical crystal 548, and an eighth harmonic (wavelength: 193 nm) is obtained from the fundamental wave and the seventh harmonic by generating a sum frequency. The arrangement smell Te, seventh harmonic wave generation B BO crystal 545, and eighth harmonic wave L BO or crystal 548 of a generator Warini, C s L i B 6 O 10 (CL BO) crystal, or L i 2 B 4 0 7 (LB 4) Yui It is also possible to use crystals.
この図 6 Aの構成例では、 4段目の非線形光学結晶 5 4 5に 3倍波と 4倍波 とが互いに異なる光路を通って入射するので、 3倍波を集光するレンズ 5 4 0 と、 4倍波を集光するレンズ 5 4 2とを別々の光路に置くことができる。 3段 目の非線形光学結晶 5 3 9で発生した 4倍波はその断面形状が Walk- of f 現象 により長円形になっている。 このため、 4段目の非線形光学結晶 5 4 5で良好 な変換効率を得るためには、 その 4倍波のビーム整形を行うことが望ましい。 この場合、 集光レンズ 5 4 0、 5 4 2を別々の光路に配置しているので、 例え ばレンズ 5 4 2としてシリンドリカルレンズ対を用いることができ、 4倍波の ビーム整形を容易に行うことが可能となる。 このため、 4段目の非線形光学結 晶 (B B O結晶) 5 4 5での 3倍波との重なりを良好にし、 変換効率を高める ことが可能である。  In the configuration example of FIG. 6A, since the third harmonic and the fourth harmonic enter the fourth-stage nonlinear optical crystal 545 through optical paths different from each other, a lens 540 that condenses the third harmonic is used. And the lens 542 that collects the fourth harmonic can be placed in separate optical paths. The cross-section of the fourth harmonic generated by the third-stage nonlinear optical crystal 539 has an elliptical shape due to the walk-of-f phenomenon. For this reason, in order to obtain good conversion efficiency in the fourth-stage nonlinear optical crystal 545, it is desirable to perform beam shaping of its fourth harmonic. In this case, the condenser lenses 540 and 542 are arranged in separate optical paths, for example, a pair of cylindrical lenses can be used as the lens 542, thereby facilitating beam shaping of the fourth harmonic. It becomes possible. For this reason, it is possible to improve the conversion efficiency by improving the overlap with the third harmonic in the fourth-stage nonlinear optical crystal (BBO crystal) 545.
さらに、 5段目の非線形光学結晶 5 4 8に入射する基本波を集光するレンズ 5 4 4と、 7倍波を集光するレンズ 5 4 7とを別々の光路に置くことができる。  Further, the lens 544 for condensing the fundamental wave incident on the fifth-stage nonlinear optical crystal 548 and the lens 545 for condensing the seventh harmonic can be placed in different optical paths.
4段目の非線形光学結晶 5 4 5で発生した 7倍波はその断面形状が Walk- of f 現象により長円形になっている。 このため、 5段目の非線形光学結晶 5 4 8で 良好な変換効率を得るためには、 その 7倍波のビーム整形を行うことが好まし い。 本実施例では、 集光レンズ 5 4 4、 5 4 7を別々の光路に配置することが できるので、 例えばレンズ 5 4 7としてシリンドリカルレンズ対を用いること ができ、 7倍波のビーム整形を容易に行うことが可能となる。 このため、 5段 目の非線形光学結晶 (L B 0結晶) 5 4 8での基本波との重なりを良好にし、 変換効率を高めることが可能である。 The seventh harmonic generated by the fourth-stage nonlinear optical crystal 545 has an elliptical cross-sectional shape due to the walk-of-f phenomenon. Therefore, in order to obtain good conversion efficiency in the fifth-stage nonlinear optical crystal 548, it is preferable to perform beam shaping of the seventh harmonic. In the present embodiment, the condenser lenses 544 and 544 can be arranged in separate optical paths, so that, for example, a pair of cylindrical lenses can be used as the lens 544, so that beam shaping of the seventh harmonic can be easily performed. Can be performed. For this reason, it is possible to improve the conversion efficiency by improving the overlap with the fundamental wave in the fifth-stage nonlinear optical crystal (LB0 crystal) 548.
なお、 2段目の非線形光学結晶 5 3 6と 4段目の非線形光学結晶 5 4 5との 間の構成は図 6 Aに限られるものではなく、 非線形光学結晶 5 3 6から発生し てダイクロイツク ·ミラー 5 3 7で反射される 3倍波と、 非線形光学結晶 5 3 6から発生してダイクロイツク ·ミラー 5 3 7を透過する 2倍波を非線形光学 結晶 539で波長変換して得られる 4倍波とが同時に非線形光学結晶 545に 入射するように、 両非線形光学結晶 536、 545間の 2つの光路長が等しく なっていれば、 いかなる構成であっても構わない。 このことは 3段目の非線形 光学結晶 539と 5段目の非線形光学結晶 548との間でも同様である。 発明者の行った実験によれば、図 6 Aの場合、各チャネル当たりの 8倍波(波 長 1 93 nm) の平均出力は、 45. 9 mWであった。 従って、 全 1 28チヤ ネルを合わせたバンドルからの平均出力は 5. 9Wとなり、 露光装置用光源と して十分な出力の、 波長 1 93 nmの紫外光を提供することができる。 Note that the configuration between the second-stage nonlinear optical crystal 536 and the fourth-stage nonlinear optical crystal 545 is not limited to that shown in FIG. 6A. Non-linear optics are used to reflect the third harmonic reflected by the mirror 537 and the second harmonic generated from the nonlinear optical crystal 536 and transmitted through the dichroic mirror 537. Any configuration is possible as long as the two optical path lengths between the nonlinear optical crystals 536 and 545 are equal so that the fourth harmonic obtained by wavelength conversion by the crystal 539 simultaneously enters the nonlinear optical crystal 545. No problem. This is the same between the third-stage nonlinear optical crystal 539 and the fifth-stage nonlinear optical crystal 548. According to the experiment performed by the inventor, in the case of FIG. 6A, the average output of the eighth harmonic (wavelength 193 nm) per channel was 45.9 mW. Therefore, the average output from the bundle including all 128 channels is 5.9 W, and it is possible to provide ultraviolet light with a wavelength of 193 nm, which has a sufficient output as a light source for an exposure apparatus.
この場合、 8倍波 (1 93 nm) の発生に、 現在、 市販品として良質の結晶 が容易に入手可能な L B 0結晶が用いられている。 この L BO結晶は、 1 93 nmの紫外光の吸収係数が非常に小さく、 結晶の光損傷が問題とならないため 耐久性の面で有利である。  In this case, LB0 crystals, which are readily available as high-quality crystals on the market, are currently used to generate the eighth harmonic (193 nm). This LBO crystal has an extremely small absorption coefficient of 193 nm ultraviolet light, and is advantageous in terms of durability since optical damage of the crystal is not a problem.
また、 8倍波 (例えば波長 1 93 nm) の発生部では L B 0結晶を角度位相 整合させて用いるが、 この位相整合角が大きいために実効非線形光学定数 (d eff) が小さくなる。 そこで、 この L BO結晶に温度制御機構を設け、 L BO結 晶を高温で用いることが好ましい。 これにより、 位相整合角を小さくすること ができる、 即ち上記定数(deff) を増加させることができ、 8倍波発生効率を 向上させることができる。  In the generation part of the eighth harmonic (for example, the wavelength of 193 nm), the LB0 crystal is used after being phase-matched. However, since the phase-matching angle is large, the effective nonlinear optical constant (d eff) becomes small. Therefore, it is preferable to provide a temperature control mechanism for the LBO crystal and use the LBO crystal at a high temperature. As a result, the phase matching angle can be reduced, that is, the constant (deff) can be increased, and the efficiency of generating the eighth harmonic can be improved.
図 6 Bの波長変換部では、 基本波 (波長 1. 57 m) →2倍波 (波長 78 5 nm) → 4倍波 (波長 392. 5 n m) → 8倍波 (波長 1 96. 25 n m) →1 0倍波 (波長 1 57 nm) の順に波長変換する。 本構成例では 2倍波発生 から 8倍波発生までの各波長変換段において、 各波長変換段に入射された波長 の 2次高調波発生を行っている。  In the wavelength converter shown in Fig. 6B, the fundamental wave (wavelength 1.57 m) → the second harmonic wave (wavelength 785 nm) → the fourth harmonic wave (wavelength 392.5 nm) → the eighth harmonic wave (wavelength 196.25 nm) ) → The wavelength is converted in the order of the 10th harmonic (wavelength: 157 nm). In this configuration example, the second harmonic generation of the wavelength incident on each wavelength conversion stage is performed in each wavelength conversion stage from the second harmonic generation to the eighth harmonic generation.
また、 本構成例では波長変換に使用する非線型光学結晶として、 基本波から 2次高調波発生により 2倍波を発生する非線形光学結晶 602として L B 0結 晶を使用し、 2倍波から 2次高調波発生により 4倍波を発生する非線形光学結 晶 6 0 4として L B O結晶を使用する。 さらに、 4倍波から 2次高調波発生に より 8倍波を発生する非線形光学結晶 6 0 9には S r 2 B e 2 B 207 ( S B B O ) 結晶を使用し、 2倍波と 8倍波とから和周波発生により 1 0倍波 (波長 1 5 7 n m) を発生する非線形光学結晶 6 1 1 には S B B 0結晶を使用する。 Also, in this configuration example, as a nonlinear optical crystal used for wavelength conversion, an LB0 crystal is used as a nonlinear optical crystal 602 that generates a second harmonic by generating a second harmonic from a fundamental wave. Nonlinear optical coupling that generates fourth harmonic by second harmonic generation LBO crystal is used as crystal 604. Further, by using the S r 2 B e 2 B 2 0 7 (SBBO) crystal is the nonlinear optical crystal 6 0 9 for generating a more eighth harmonic wave from the fourth harmonic to the second harmonic generation, the second harmonic and 8 The SBB0 crystal is used for the nonlinear optical crystal 611 that generates a 10th harmonic (wavelength: 157 nm) by sum frequency generation from the harmonic.
なお、 非線形光学結晶 6 0 2から発生する 2倍波は、 集光レンズ 6 0 3を通 つて非線形光学結晶 6 0 4に入射し、 この非線形光学結晶 6 0 4は前述の 4倍 波と波長変換されない 2倍波とを発生する。 次に、 ダイクロイツク * ミラー 6 0 5を透過する 2倍波は集光レンズ 6 0 6を通るとともに、 ダイクロイツク ミラー 6 0 7で反射されて非線形光学結晶 6 1 1 に入射する。 一方、 ダイク口 イツク · ミラー 6 0 5で反射された 4倍波は、 集光レンズ 6 0 8を通って非線 形光学結晶 6 0 9に入射し、 ここで発生される 8倍波は集光レンズ 6 1 0、 及 びダイクロイツク ■ミラー 6 0 7を通って非線形光学結晶 6 1 1 に入射する。 さらに非線形光学結晶 6 1 1は、 ダイクロイツク ■ミラー 6 0 7で同軸に合成 される 2倍波と 8倍波とから和周波発生により 1 0倍波 (波長 1 5 7 n m ) を 発生する。  The second harmonic generated from the nonlinear optical crystal 602 enters the nonlinear optical crystal 604 through the condenser lens 603, and the nonlinear optical crystal 604 has the above-described fourth harmonic and wavelength. Generates second harmonics that are not converted. Next, the second harmonic transmitted through the dichroic * mirror 605 passes through the condenser lens 606, is reflected by the dichroic mirror 607, and enters the nonlinear optical crystal 611. On the other hand, the fourth harmonic reflected by the dich aperture mirror 605 enters the nonlinear optical crystal 609 through the condenser lens 608, and the eighth harmonic generated here is collected. Optical lens 610 and dichroic ■ It enters the nonlinear optical crystal 611 through the mirror 607. Further, the nonlinear optical crystal 611 generates a 10th harmonic (wavelength: 157 nm) from the second harmonic and the eighth harmonic coaxially synthesized by the dichroic mirror 607 by generating a sum frequency.
ところで、 本構成例では 2段目の非線形光学結晶 6 0 4から発生する 2倍波 と 4倍波とをダイクロイツク ·ミラー 6 0 5で分岐することで、 ここを透過し た 2倍波と、 4倍波を非線形光学結晶 6 0 9で波長変換して得られる 8倍波と が互いに異なる光路を通って 4段目の非線形光学結晶 6 1 1 に入射するように 構成したが、 ダイクロイツク ' ミラー 6 0 5、 6 0 7を用いずに 4つの非線形 光学結晶 6 0 2、 6 0 4、 6 0 9、 6 1 1を同一光軸上に配置しても良い。 但し、 本構成例では 2段目の非線形光学結晶 6 0 4で発生した 4倍波はその 断面形状が Walk-of i現象により長円形になっている。 このため、 このビームを 入力とする 4段目の非線形光学結晶 6 1 1で良好な変換効率を得るためには、 入射ビームとなる 4倍波のビーム形状を整形し、 2倍波との重なリを良好にす ることが望ましい。 本構成例では、 集光レンズ 6 0 6、 6 0 8を別々の光路に 配置することができるので、 例えばレンズ 6 0 8としてシリンドリカルレンズ を用いることが可能になり、 4倍波のビーム整形を容易に行うことができる。 このため、 4段目の非線形光学結晶 6 1 1での 2倍波との重なりを良好にし、 変換効率を高めることが可能である。 By the way, in the present configuration example, the second harmonic and the fourth harmonic generated from the second-stage nonlinear optical crystal 604 are branched by the dichroic mirror 605 so that the second harmonic transmitted therethrough Although the fourth harmonic is obtained by wavelength-converting the fourth harmonic with the nonlinear optical crystal 609, and is incident on the fourth-stage nonlinear optical crystal 611 through different optical paths, the dichroic 'Four non-linear optical crystals 62, 604, 609, and 611 may be arranged on the same optical axis without using the mirrors 605 and 607. However, in the present configuration example, the fourth harmonic generated in the second-stage nonlinear optical crystal 604 has an elliptical cross-sectional shape due to the walk-of phenomenon. Therefore, in order to obtain good conversion efficiency with the fourth-stage nonlinear optical crystal 611 using this beam as an input, the beam shape of the fourth harmonic wave, which is the incident beam, is shaped and overlapped with the second harmonic wave It is desirable to improve the quality. In this configuration example, the condenser lenses 606 and 608 are placed on separate optical paths. Since the lenses can be arranged, for example, a cylindrical lens can be used as the lens 608, and beam shaping of the fourth harmonic can be easily performed. For this reason, it is possible to make the overlap with the second harmonic in the fourth-stage nonlinear optical crystal 6 11 1 good, and to increase the conversion efficiency.
なお、 上記図 6 A、 図 6 Bに示される波長変換部は一例であって、 本発明の 波長変換部の構成がこれに限定されないことは勿論である。 例えば、 バンドル 一ファイバ 1 7 3の出力端から射出される波長 1 . 5 7 mの基本波を非線形 光学結晶を用いて 1 0倍波の高調波発生を行い、 F 2レーザと同じ波長である 1 5 7 n mの紫外光を発生することにしてもよい。 The wavelength converters shown in FIGS. 6A and 6B are merely examples, and it goes without saying that the configuration of the wavelength converter of the present invention is not limited to this. For example, performs harmonic generation 1 0 harmonic by using a nonlinear optical crystal a fundamental wave having a wavelength 1. 5 7 m emitted from the output end of the bundle one fiber 1 7 3, is at the same wavelength as the F 2 laser Ultraviolet light of 157 nm may be generated.
図 2に戻り、 前記ビームモニタ機構 1 6 4は、 ここではフアブリペロー ·ェ タロン (Fabry-Pero t e t alon:以下、 「エタロン素子 j ともいう)及びフ才卜ダ ィオード等の光電変換素子から成るエネルギモニタ (いずれも図示省略) から 構成されている。 ビームモニタ機構 1 6 4を構成するエタロン素子に入射した 光は、 エタロン素子の共鳴周波数と入射光の周波数との周波数差に対応した透 過率で透過し、 その透過光強度を検出するフ才卜ダイオード等の出力信号がレ 一ザ制御装置 1 6 Bに供給される。 レーザ制御装置 1 6 Bではこの信号に所定 の信号処理を施すことにより、 ビームモニタ機構 1 6 4、 具体的にはエタロン 素子に対する入射光の光学特性に関する情報 (具体的には、 入射光の中心波長 及び波長幅 (スペクトル半値幅) 等) を得る。 そして、 この光学特性に関する 情報は、 リアルタイムで主制御装置 5 0に通知される。  Returning to FIG. 2, the beam monitor mechanism 164 is composed of a photoelectric conversion element such as a Fabry-Pero etalon (hereinafter also referred to as “etalon element j”) and a photoelectric conversion element such as a photodiode. The light incident on the etalon element constituting the beam monitor mechanism 16 4 has a transmittance corresponding to the frequency difference between the resonance frequency of the etalon element and the frequency of the incident light. An output signal of a photodiode or the like for detecting the transmitted light intensity is supplied to a laser controller 16 B. The laser controller 16 B performs a predetermined signal processing on this signal. Thus, information on the optical characteristics of the incident light to the beam monitor mechanism 16 4, specifically, the etalon element (specifically, the center wavelength and the wavelength width of the incident light (spectral half width), etc.) Then, the information on the optical characteristics is notified to the main controller 50 in real time.
エタ口ン素子の生成する透過光強度の周波数特性は、 雰囲気の温度や圧力の 影響を受け、 特にその共鳴周波数(共鳴波長) は温度依存性がある。 このため、 このエタロン素子の検出結果に基づいてレーザ光源 1 6 O Aから発振されるレ 一ザ光の中心波長を精度良く制御するためには、 この共鳴波長の温度依存性を 調べておくことが重要である。 本実施形態では、 この共鳴波長の温度依存性を 予め計測し、 この計測結果が温度依存性マップとして主制御装置 5 0に併設さ れた記憶装置としてのメモリ 5 1 (図 1参照) に記憶されている。 なお、 この 温度依存性マップは、 メモリ 5 1内にテーブルの形で持たせても良いし、 関数 又は係数として持たせても良い。 The frequency characteristics of the transmitted light intensity generated by the ETA element are affected by the temperature and pressure of the atmosphere. In particular, the resonance frequency (resonance wavelength) is temperature-dependent. Therefore, in order to accurately control the center wavelength of the laser light oscillated from the laser light source 16 OA based on the detection result of this etalon element, it is necessary to examine the temperature dependence of the resonance wavelength. is important. In the present embodiment, the temperature dependence of the resonance wavelength is measured in advance, and the measurement result is attached to the main controller 50 as a temperature dependence map. It is stored in a memory 51 (see FIG. 1) as a storage device. The temperature dependence map may be stored in the memory 51 in the form of a table, or may be stored as a function or a coefficient.
そして、 主制御装置 5 0では、 ビームモニタ機構 1 6 4の後述する絶対波長 キャリブレーションの際等に、 温度依存性マップに基づいて、 エタロン素子の 透過率が最大となる共鳴波長 (検出基準波長) が設定波長に正確に一致するよ うにするため、 レーザ制御装置 1 6 Bに指示を与えて、 ビームモニタ機構 1 6 4内のエタロン素子の温度を積極的に制御するようになっている。  Then, main controller 50 uses the temperature dependence map to determine the resonance wavelength at which the transmittance of the etalon element becomes maximum (detection reference wavelength) at the time of absolute wavelength calibration of beam monitor mechanism 164, which will be described later. In order to make exactly match the set wavelength, an instruction is given to the laser controller 16 B to actively control the temperature of the etalon element in the beam monitor mechanism 164.
また、 ビームモニタ機構 1 6 4を構成するエネルギモニタの出力は、 主制御 装置 5 0に供給されており、 主制御装置 5 0ではエネルギモニタの出力に基づ いてレーザ光のエネルギパワーを検出し、 レーザ制御装置 1 6 Bを介して D F B半導体レーザ 1 6 O Aで発振されるレーザ光の光量を必要に応じて制御した り、 D F B半導体レーザ 1 6 O Aをオフしたりする。 但し、 本実施形態では、 後述するように、 通常の光量制御 (露光量制御) は、 主として光量制御装置 1 6 Cにより、 E O M 1 6 0 Cの出力パルス光のピークパワーあるいは周波数の 制御、 又は光増幅部 1 6 1を構成する各ファイバ増幅器の出力光のオン ·オフ 制御によって行われるので、 レーザ光のエネルギパワーが何らかの原因で大き く変動した場合に主制御装置 5 0がレーザ制御装置 1 6 Bを上記の如く制御す ることとなる。  The output of the energy monitor constituting the beam monitor mechanism 164 is supplied to the main controller 50. The main controller 50 detects the energy power of the laser beam based on the output of the energy monitor. The DFB semiconductor laser 16 OA controls the amount of laser light oscillated by the DFB semiconductor laser 16 OA via the laser controller 16 B as necessary, or turns off the DFB semiconductor laser 16 OA. However, in the present embodiment, as will be described later, normal light amount control (exposure amount control) is mainly performed by the light amount control device 16 C by controlling the peak power or frequency of the output pulse light of the EOM 160 C, or Since the output power of each fiber amplifier constituting the optical amplifying unit 16 1 is controlled by on / off control, when the energy power of the laser light fluctuates greatly for some reason, the main controller 50 is controlled by the laser controller 1. 6B will be controlled as described above.
前記吸収セル 1 6 5は、 D F B半導体レーザ 1 6 O Aの発振波長の絶対波長 キャリブレーション、 すなわちビームモニタ機構 1 6 4の絶対波長キヤリブレ ーシヨンのための絶対波長源である。 本実施形態では、 この吸収セル 1 6 5と して、 レーザ光源として発振波長 1 . 5 4 4 At mの D F B半導体レーザ 1 6 0 Aが用いられている関係から、 この波長近傍の波長帯域に吸収線が密に存在す るアセチレンの同位体が用いられている。  The absorption cell 165 is an absolute wavelength source for the absolute wavelength calibration of the oscillation wavelength of the DFB semiconductor laser 16OA, that is, the absolute wavelength calibration of the beam monitor mechanism 164. In the present embodiment, since the absorption cell 165 uses a DFB semiconductor laser 160 A having an oscillation wavelength of 1.544 Atm as a laser light source, the absorption cell 165 has a wavelength band near this wavelength. Acetylene isotopes with dense absorption lines are used.
なお、 後述するように、 レーザ光の波長のモニタ用の光として、 基本波とと もにあるいはこれに代えて、 上述した波長変換部 1 63の中間波 (2倍波、 3 倍波、 4倍波等) あるいは波長変換後の光を選択する場合には、 それらの中間 波等の波長帯域に吸収線が密に存在する吸収セルを用いれば良い。 例えば、 波 長のモニタ用の光として、 3倍波を選択する場合には、 波長503门 111〜53 0 nmの近傍に吸収線が密に存在するヨウ素分子を吸収セルとして用い、 その ヨウ素分子の適切な吸収線を選んでその波長を絶対波長とすれば良い。 As described later, a fundamental wave and a fundamental wave are used as light for monitoring the wavelength of the laser light. Alternatively or in place of this, when selecting the above-described intermediate wave (second harmonic, third harmonic, fourth harmonic, etc.) of the wavelength conversion unit 163 or the light after wavelength conversion, the intermediate wave, etc. It is sufficient to use an absorption cell in which absorption lines exist densely in the above wavelength band. For example, when the third harmonic is selected as the light for monitoring the wavelength, an iodine molecule having an absorption line in the vicinity of a wavelength of 50353111 to 530 nm is used as an absorption cell, and the iodine molecule is used. The appropriate absorption line may be selected and its wavelength may be used as the absolute wavelength.
また、 絶対波長源としては、 吸収セルに限らず、 絶対波長光源を用いても良 い。  Further, the absolute wavelength source is not limited to the absorption cell, and an absolute wavelength light source may be used.
前記レーザ制御装置 1 6 Bは、 主制御装置 50の管理の下、 ビームモニタ機 構 1 64の出力に基づいてレーザ光の中心波長及び波長幅(スぺク卜ル半値幅) を検出し、 中心波長が所望の値 (設定波長) となるように D F B半導体レーザ 1 6 OAの温度制御 (及び電流制御) をフィードバック制御にて行う。 本実施 形態では、 D F B半導体レーザ 1 6 OAの溫度を 0. 00 1 °C単位で制御する ことが可能となっている。  Under the control of the main controller 50, the laser controller 16B detects the center wavelength and the wavelength width (spectral half width) of the laser beam based on the output of the beam monitor mechanism 164, The temperature control (and current control) of the DFB semiconductor laser 16 OA is performed by feedback control so that the center wavelength becomes a desired value (set wavelength). In this embodiment, the intensity of the DFB semiconductor laser 16 OA can be controlled in 0.001 ° C. units.
また、 このレーザ制御装置 1 6 Bは、 主制御装置 50からの指示に応じて、 D F B半導体レーザ 1 60 Aのパルス出力と連続出力との切替、 及びそのパル ス出力時における出力間隔やパルス幅などの制御を行うとともに、 パルス光の 出力変動を補償するように、 D F B半導体レーザ 1 6 OAの発振制御を行う。 このようにして、 レーザ制御装置 1 6 Bでは、 発振波長を安定化して一定の 波長に制御したり、 あるいは出力波長を微調整する。 逆に、 このレーザ制御装 置 1 6 Bは、 主制御装置 50からの指示に応じて、 D F B半導体レーザ 1 60 Aの発振波長を積極的に変化させてその出力波長を調整することもある。 これ については、 更に後述する。  In addition, the laser controller 16B switches between the pulse output and the continuous output of the DFB semiconductor laser 160A according to the instruction from the main controller 50, and the output interval and pulse width at the time of the pulse output. Controls the oscillation of the DFB semiconductor laser 16 OA so as to compensate for the output fluctuation of the pulsed light. In this way, the laser controller 16B stabilizes the oscillation wavelength to control it at a constant wavelength, or fine-tunes the output wavelength. Conversely, the laser control device 16B may adjust the output wavelength by positively changing the oscillation wavelength of the DFB semiconductor laser 160A in accordance with an instruction from the main control device 50. This is described further below.
次に、 D F B半導体レーザで発振されるレーザ光の波長安定化制御方法につ いて説明する。  Next, a method for controlling wavelength stabilization of laser light oscillated by a DFB semiconductor laser will be described.
まず、 波長安定化制御の前提となるビームモニタ機構 1 64内のエタロン素 子の絶対波長キヤリプレーションについて説明する。 First, the etalon element in the beam monitor mechanism 164, which is the premise of wavelength stabilization control, The absolute wavelength calibration of the child will be described.
前述の如く、 本実施形態では、 D F B半導体レーザ 1 6 O Aの発振波長及び ビームモニタ機構 1 6 4内のエタロン素子の共鳴波長 (A res) の温度依存性が 予め測定され、 その測定結果がメモリ 5 1に記憶されている。 As described above, in this embodiment, the temperature dependence of the oscillation wavelength of the DFB semiconductor laser 16 OA and the resonance wavelength (A res ) of the etalon element in the beam monitor mechanism 164 is measured in advance, and the measurement results are stored in the memory. 5 Memorized in 1.
そこで、 エタロン素子の絶対波長キャリブレーションに際して、 主制御装置 5 0では、 レーザ制御装置 1 6 Bを介して D F B半導体レーザ 1 6 O Aを発振 させた状態で、 レーザ制御装置 1 6 Bを介して吸収セル 1 6 5の透過率が最大 となる設定波長 (A set) に最も近い、 あるいは一致する波長 (A ref) の吸収線 を選択するとともに、 そのときエタロン素子の透過率が最大となるように、 レ 一ザ制御装置 1 6 Bに指示を与えてビームモニタ機構 1 6 4内のエタロン素子 の温度を制御する。すなわち、 エタロン素子の共鳴波長(A res)が絶対波長(λ ref) を用いてキャリブレーションする。 これにより、 エタロン素子の検出基準 波長である A resが絶対波長 (λ「βί) に一致する。 Therefore, at the time of absolute wavelength calibration of the etalon element, the main controller 50 absorbs the laser light through the laser controller 16 B while the DFB semiconductor laser 16 OA is oscillated via the laser controller 16 B. The absorption line of the wavelength (A ref ) closest to or matching the set wavelength (A set ) at which the transmittance of the cell 165 becomes the maximum is selected. An instruction is given to the laser controller 16B to control the temperature of the etalon element in the beam monitor mechanism 164. That is, the resonance wavelength (A res ) of the etalon element is calibrated using the absolute wavelength (λ ref ). Thus, A res is the detection reference wavelength of the etalon device matches the absolute wavelength (lambda "βί).
ここで、 上記の絶対波長キャリブレーションを行う際に、 主制御装置は、 レ 一ザ制御装置 1 6 Βを介して D F Β半導体レーザ 1 6 0 Αの発振波長を所定範 囲内で変化させることとしても良い。 このようにすると、 発振開始時点で D F Β半導体レーザ 1 6 O Aの発振波長が設定波長から大きくずれていたような場 合であっても速やかに吸収セル 1 6 5の透過率が最大となる設定波長 (A set) に最も近い、 あるいは一致する波長 (A rei) の吸収線を選択することが可能に なり、 絶対波長キャリブレーションを短時間で完了することができる。 Here, when performing the above absolute wavelength calibration, the main controller changes the oscillation wavelength of the DF {semiconductor laser 160} through the laser controller 16 within a predetermined range. Is also good. In this way, even when the oscillation wavelength of the DF Β semiconductor laser 16 OA is greatly deviated from the set wavelength at the start of the oscillation, the setting is such that the transmittance of the absorption cell 16 5 is quickly maximized. This makes it possible to select the absorption line at the wavelength (A rei ) closest to or coincident with the wavelength (A set ), so that the absolute wavelength calibration can be completed in a short time.
そして、 上記の絶対波長キャリブレーションが完了すると、 主制御装置 5 0 ではメモリ 5 1内に記憶されているエタロン素子の共鳴波長 (A res) の温度依 存性のデータを用いてレーザ制御装置 1 6 Bを介してエタロン素子の温度制御 を行い、 エタロン素子の共鳴波長 (A res) を設定波長 (A set) に設定する設定 波長キヤリブレーションを実行する。 When the absolute wavelength calibration is completed, the main controller 50 uses the temperature-dependent data of the resonance wavelength (A res ) of the etalon element stored in the memory 51 to store the laser controller 1. 6 Control the temperature of the etalon element via B, and execute the setting wavelength calibration to set the resonance wavelength (A res ) of the etalon element to the set wavelength (A set ).
このように、 本実施形態の波長安定化制御方法によると、 エタロン素子の共 鳴波長(A res)、すなわち検出基準波長を設定波長に確実に一致させることがで さる。 Thus, according to the wavelength stabilization control method of the present embodiment, the etalon element The ringing wavelength (A res ), that is, the detection reference wavelength can be surely matched with the set wavelength.
そして、 それ以後は、 レーザ制御装置 1 6 Bにより、 設定波長キヤリブレー シヨンが完了したエタロン素子の検出値 (ビームモニタ機構 1 6 4のモニタ結 果) に基づいて D F B半導体レーザ 1 6 0 Aの温度制御及び電流制御がフィー ドバック制御にて行われるようになつている。 ここで、 レーザ制御装置 1 6 B が、 D F B半導体レーザ 1 6 O Aの温度制御のみでなく、 供給電流 (ドライブ 電流) の制御をも行うのは、 電流制御による方が応答性が良いためである。 例えば、 前者によれば、 波長変動による投影光学系 P Lの収差 (結像特性) の発生、 又はその変動が防止され、 パターン転写中にその像特性 (像質などの 光学的特性) が変化することがなくなる。  After that, the temperature of the DFB semiconductor laser 160 A is controlled by the laser controller 16 B based on the detected value of the etalon element for which the set wavelength calibration has been completed (the monitoring result of the beam monitor mechanism 164). Control and current control are performed by feedback control. Here, the reason why the laser controller 16 B controls not only the temperature of the DFB semiconductor laser 16 OA but also the supply current (drive current) is that the responsiveness is better with the current control. . For example, according to the former, the occurrence (or image change) of the aberration of the projection optical system PL due to wavelength fluctuation or its fluctuation is prevented, and the image characteristic (optical characteristics such as image quality) changes during pattern transfer. Disappears.
また、 後者によれば、 露光装置が組立、 調整される製造現場と露光装置の設 置場所 (納入先) との標高差や気圧差、 更には環境 (クリーンルーム内の雰囲 気) の違いなどに応じて生じる投影光学系 P Lの結像特性 (収差など) の変動 を相殺でき、 納入先で露光装置の立ち上げに要する時間を短縮することが可能 になる。 更に、 後者によれば、 露光装置の稼働中に、 露光用照明光の照射、 及 び大気圧変化などに起因して生じる投影光学系 P Lの収差、 投影倍率、 及び焦 点位置などの変動も相殺でき、 常に最良の結像状態でパターン像を基板上に転 写することが可能となる。  According to the latter, the difference in elevation and pressure between the manufacturing site where the exposure equipment is assembled and adjusted and the location where the exposure equipment is installed (delivery destination), as well as differences in the environment (the atmosphere in the clean room), etc. Variations in the imaging characteristics (such as aberrations) of the projection optical system PL that occur depending on the situation can be offset, and the time required to start up the exposure apparatus at the delivery destination can be reduced. Furthermore, according to the latter, during the operation of the exposure apparatus, there are also variations in the aberration, projection magnification, and focal position of the projection optical system PL caused by irradiation of the exposure illumination light and changes in the atmospheric pressure. It is possible to cancel each other and transfer the pattern image onto the substrate in the best imaging state at all times.
前記光量制御装置 1 6 Cは、 前述したように、 光増幅部 1 6 1内のファイバ 増幅器 1 6 8 n、 1 7 1 nの光出力を検出する光電変換素子 1 8 0、 1 8 1の出 力に基づいて各励起用半導体レーザ (1 7 8、 1 7 4 ) のドライブ電流をフィ 一ドバック制御して、 各増幅段毎に各チャネルのファイバ増幅器の増幅率を一 定化させる機能と、 波長変換部 1 6 3途中でビームスプリッタにより分岐され た光を検出する光電変換素子 1 8 2の出力信号に基づいて、 励起用半導体レー ザ 1 7 8、 1 7 4の少なくとも一方のドライブ電流をフィードバック制御して 予定される所定の光強度を各増幅段にフィードバックし、 所望の紫外光出力を 安定させる機能とを有する。 As described above, the light amount control device 16C is provided with the photoelectric conversion elements 18 0 and 18 1 for detecting the optical outputs of the fiber amplifiers 16 68 n and 17 1 n in the optical amplification section 16 1. Based on the output, the drive current of each pumping semiconductor laser (178, 174) is feedback-controlled to stabilize the gain of the fiber amplifier of each channel for each amplification stage. Based on the output signal of the photoelectric conversion element 182, which detects the light split by the beam splitter in the middle of the wavelength conversion section 163, the drive current of at least one of the semiconductor lasers for excitation 1778, 174 is determined. Feedback control It has a function of feeding back a predetermined predetermined light intensity to each amplification stage and stabilizing a desired ultraviolet light output.
更に、 本実施形態では、 光量制御装置 1 6 Cは、 次のような機能をも有して いる。  Further, in the present embodiment, the light amount control device 16C also has the following functions.
すなわち、 光量制御装置 1 6 Cは、  That is, the light amount control device 16 C
① 主制御装置 5 0からの指示に応じて、 バンドル一ファイバ 1 7 3を構成す る各チャネルのファイバの出力、 すなわち各光経路 1 7 2 nの出力を個別に才 ン 'オフ制御することにより、 バンドル全体での平均光出力の制御を行う機能(1) In accordance with an instruction from the main controller 50, the output of the fiber of each channel constituting the bundle 1 fiber 173, that is, the output of each optical path 172 n is individually turned off. Function to control the average light output of the entire bundle
(以下、 便宜上 「第 1の機能」 と呼ぶ) と、 (Hereinafter referred to as "the first function" for convenience)
② 主制御装置 5 0からの指示に応じて、 E O M 1 6 0 Cから出力されるパル ス光の周波数を制御することにより、 単位時間当たりの光増幅部 1 6 1の各チ ャネルの平均光出力(出力ェネルギ)、すなわち単位時間当たりの各光経路 1 7 2 nからの出力光の強度を制御する機能 (以下、 便宜上 「第 2の機能」 と呼ぶ) と、 (2) By controlling the frequency of the pulse light output from the EOM 160 C in response to an instruction from the main controller 50, the average light of each channel of the optical amplifying unit 16 1 per unit time is controlled. Output (output energy), that is, a function of controlling the intensity of output light from each optical path 17 2 n per unit time (hereinafter referred to as “second function” for convenience)
③ 主制御装置 5 0からの指示に応じて、 E O M 1 6 0 Cから出力されるパル ス光のピークパワーを制御することにより、 単位時間当たりの光増幅部 1 6 1 の各チャネルの平均光出力(出力ェネルギ)、すなわち単位時間当たりの各光経 路 1 7 2„からの出力光の強度を制御する機能(以下、 便宜上 「第 3の機能」 と 呼ぶ) と、 を有する。  ③ By controlling the peak power of the pulse light output from the EOM 160 C in response to the instruction from the main controller 50, the average light of each channel of the optical amplification unit 16 1 per unit time is controlled. An output (output energy), that is, a function of controlling the intensity of output light from each optical path 172 „per unit time (hereinafter, referred to as“ third function ”for convenience).
以下、 上記第 1〜第 3の機能について、 詳述する。  Hereinafter, the first to third functions will be described in detail.
まず、光量制御装置 1 6 Cは、上記第 1の機能における各光経路 1 7 2 Πの出 力のオン ·オフを、各チャネルの最終段のファイバ増幅器 1 7 1 ηからの出力を オン ·オフすることにより行う。 この場合、 光量制御装置 1 6 Cでは、 フアイ バ増幅器励起用半導体レーザ 1 7 4をオン■オフする、 すなわち半導体レーザ 1 7 4からの励起光の強度を所定レベルと零レベルとのいずれかに択一的に設 定することにより行うこともできるし、 半導体レーザ 1 7 4のドライブ電流の 電流値を調整することにより、 半導体レーザ 1 7 4からの励起光の強度をファ ィバ増幅器 1 7 1 nが増幅可能状態となる第 1 レベルと、ファイバ増幅器 1 7 1 。が増幅不能状態となる第 2レベルとのいずれかに択一的に設定することによ り行なうこともできる。 増幅不能状態では、 光の吸収が大きくなリ、 ファイバ 増幅器からの出力は殆ど零となるので、各光経路 1 7 2 nの出力がオフとなる。 半導体レーザ 1 7 4をオン ·オフする場合には、 半導体レーザ 1 7 4をオフ にしている状態では、 その分の消費電力はなくなるので、 エネルギーセイブが 可能になる。 一方、 半導体レーザ 1 7 4からの励起光の強度を上記第 1 レベル と第 2レベルとで切り換える場合には、 第 1 レベルと第 2レベルとは固定値で あっても良いが、 固定値でなくても良い。 すなわち、 ファイバ増幅器では、 励 起光の強度がある値を境として、 上にいくか下にいくかで、 増幅可能状態とな るか増幅不能状態となるかが定まるからである。 First, the light quantity control device 16C turns on / off the output of each optical path 1772 in the first function, and turns on / off the output from the fiber amplifier 17 1 η at the last stage of each channel. Perform by turning off. In this case, the light amount control device 16C turns on / off the semiconductor laser for excitation of the fiber amplifier 174, that is, sets the intensity of the excitation light from the semiconductor laser 174 to one of a predetermined level and a zero level. It can also be done by setting it as an alternative, or the drive current of the semiconductor laser 174 By adjusting the current value, the intensity of the pumping light from the semiconductor laser 174 can be adjusted to the first level at which the fiber amplifier 171 n can be amplified, and the fiber amplifier 171. Alternatively, it can be performed by setting either the first level or the second level at which amplification is disabled. In the non-amplification state, the light absorption becomes large, and the output from the fiber amplifier becomes almost zero, so that the output of each optical path 172 n is turned off. When the semiconductor laser 174 is turned on and off, the power is not consumed in the state where the semiconductor laser 174 is turned off, so that energy can be saved. On the other hand, when the intensity of the pump light from the semiconductor laser 174 is switched between the first level and the second level, the first level and the second level may be fixed values. You don't have to. In other words, in a fiber amplifier, whether the state of amplification is possible or not is determined by going up or down from a certain value of the excitation light intensity.
この光量制御装置 1 6 Cの第 1の機能によると、 バンドル全体での平均光出 力 (光量) は、 最大出力光量の 1 / 1 2 8刻みで (約 1 %以下毎) に制御可能 である。 すなわち、 ダイナミックレンジが〗〜 1 1 2 8という広い範囲に設 定可能である。各光経路 1 7 2 nは同じ構成部材を用いて構成されているので、 設計上は、各光経路 1 7 2 nの光出力は等しくなる害であり、上記 1 / 1 2 8刻 みの光量制御はリニァリティの良いものとなる。 According to the first function of the light quantity control device 16C, the average light output (light quantity) of the entire bundle can be controlled at 1 / 128th of the maximum output light quantity (about 1% or less). is there. That is, the dynamic range can be set in a wide range from〗 to 1 128. Since each optical path 172 n is configured by using the same component, the optical output of each optical path 172 n is equal to the harm from the viewpoint of design. The light quantity control has good linearity.
また、本実施形態では、 光増幅部 1 6 1の出力、 すなわちバンドル-ファイバ 1 7 3の出力を波長変換する波長変換部 1 6 3が設けられているが、 この波長 変換部 1 6 3出力は、各光経路 1 7 2 nの出力、すなわちファイバ増幅器 1 7 1 nの出力がオンであるファイバ数に比例するため、設定光量に対し、最大出力光 量の 1 / 1 2 8刻みのリニアな (約 1 %ごと) 制御が原則的には可能となる害 である。 In the present embodiment, the wavelength converter 163 for wavelength-converting the output of the optical amplifier 161, that is, the output of the bundle-fiber 173 is provided. Is proportional to the number of fibers with the output of each optical path 172 n , that is, the output of the fiber amplifier 171 n turned on.Therefore, for the set light amount, a linear output of 1/128 of the maximum output light amount It is a harm that control is possible in principle.
しかしながら、実際には、製造上の誤差等に起因して各光経路 1 7 2 nの出力 のばらつきや、各光経路 1 7 2 nの出力に対する波長変換効率のばらつき等が存 在する可能性が高いので、 予め各光ファイバ (光経路 1 72n) の出力のばらつ き、 及び各光ファイバ出力に対する波長変換効率のばらつき等に起因する出力 のばらつきを測定し、 その測定結果に基づいて各光ファイバからの光出力のォ ン ·オフ状況に対応する波長変換部 1 63からの光出力の強度のマップ (オン にするファイバグループに対応した出力強度の換算表) である第 1の出力強度 マップを作成し、 その第 1の出力強度マップを主制御装置 50に併設されたメ モリ 5 1内に格納している。 なお、 この第 1の出力強度マップは、 メモリ 5 1 内にテーブルの形で持たせても良いし、 関数又は係数として持たせても良い。 なお、 後述する第 2、 第 3の出力強度マップも同様である。 However, in practice, variations in the output of each optical path 172 n and variations in the wavelength conversion efficiency with respect to the output of each optical path 172 n exist due to manufacturing errors and the like. Because there is a high possibility that there is a high possibility, the output variation of each optical fiber (optical path 172 n ) and the output variation due to the wavelength conversion efficiency variation for each optical fiber output are measured in advance. This is a map of the intensity of the optical output from the wavelength converter 163 corresponding to the on / off status of the optical output from each optical fiber based on the result (a conversion table of the output intensity corresponding to the fiber group to be turned on). A first output intensity map is created, and the first output intensity map is stored in the memory 51 attached to the main controller 50. This first output intensity map may be stored in the memory 51 in the form of a table, or may be stored as a function or a coefficient. The same applies to the second and third output intensity maps described later.
そして、 光量制御装置では、 本第 1の機能により光量制御を行う際に、 主制 御装置 50から与えられる設定光量と上記の出力強度マップとに基づいて光量 制御を行うようになっている。  Then, in the light amount control device, when performing the light amount control by the first function, the light amount control is performed based on the set light amount given from the main control device 50 and the output intensity map.
また、 光量制御装置 1 6 Cは、 上記第 2の機能における EOM 1 60じから 出力されるパルス光の周波数制御を、 EOM 1 60 Cに印加する矩形波 (電圧 パルス) の周波数を変えることにより行う。 EOM 1 60 Cから出力されるパ ルス光の周波数は EOM 1 60 Cに印加する電圧パルスの周波数に一致するた め、 印加電圧を制御することにより出力パルス光の周波数を制御することとし たものである。  The light quantity control device 16C controls the frequency control of the pulse light output from the EOM 160 in the second function by changing the frequency of the rectangular wave (voltage pulse) applied to the EOM 160C. Do. Since the frequency of the pulse light output from the EOM 160 C matches the frequency of the voltage pulse applied to the EOM 160 C, the frequency of the output pulse light is controlled by controlling the applied voltage. It is.
本実施形態の場合、 前述の如く、 EOM 1 60 Cに印加する矩形波の周波数 は 1 00 k H zである。 例えば、 この周波数を 1 1 0 k H zとすれば、 EOM 1 60 Cから出力される単位時間あたりの光パルス数は 1 0%増加し、 このパ ルスが、 前述と同様に、 分岐及び遅延部 1 67により各パルス毎に順次チヤネ ル 0からチャネル 1 27の総計 1 28チャネルに振り分けられる結果、 各チヤ ネルについて見ても単位時間当たりのパルス光は 1 0%増加し、 光パルス 1個 あたりの光エネルギが同一、すなわちパルス光のピークパワーが一定であれば、 単位時間当たりの各光経路 1 72nの出力光強度 (光量) も 1 0%増加する。 また、 本実施形態では、 光増幅部 1 6 1の各チャネルの出力光の波長変換を 行う波長変換部 1 63が設けられているが、 この波長変換部 1 63の単位時間 当たりの出力光の光量は、 ピークパワーが一定であれば、 各チャネルの出力パ ルスの周波数に比例する。 このように、 本第 2の機能による光量制御は、 リニ ァリティに優れた制御となる。 In the case of the present embodiment, as described above, the frequency of the rectangular wave applied to the EOM 160 C is 100 kHz. For example, if this frequency is set to 110 kHz, the number of optical pulses output from the EOM 160 C per unit time increases by 10%. As a result of division by channel 167 from channel 0 to channel 128 for a total of 128 channels for each pulse, pulse light per unit time increases by 10% for each channel and one light pulse If the light energy per unit light is the same, that is, if the peak power of the pulsed light is constant, the output light intensity (light amount) of each optical path 172 n per unit time also increases by 10%. Further, in the present embodiment, the wavelength conversion unit 163 for performing wavelength conversion of the output light of each channel of the optical amplification unit 161 is provided. The light intensity is proportional to the frequency of the output pulse of each channel if the peak power is constant. As described above, the light quantity control by the second function is excellent in linearity.
但し、 EON/M 60 Cから出力されるパルス光は、 遅延部 1 67を経て、 フ アイバ増幅器 1 68„、 1 7 1 nの入力となるため、 実際には、 上述のようなリ ニァリティが得られるとは限らない。 すなわち、 一般に、 ファイバ増幅器の増 幅利得は、 入力光強度依存性があるため、 EOM 1 60 Cの出力光の周波数を 変えると、 ファイバ増幅器 1 68n、 1 7 1 nの入力光強度が変化し、 その結果 ファイバ増幅器 1 68n、 1 7 1 nから出力されるパルス光のピークパワーが変 化する場合があるからである。 ファイバ増幅器 1 68n、 1 7 1„を適切に設計 することによリ、このピークパワー変化を小さく抑えることも可能ではあるが、 ファイバ増幅器の光出力効率等の他の性能を低下させる場合もある。 However, the pulse light output from the EON / M 60 C is, via the delay unit 1 67, full multiplexing amplifier 1 68 ", since the input of the 1 7 1 n, in practice, re Niariti is as described above That is, in general, the gain of a fiber amplifier depends on the input light intensity, and therefore, when the frequency of the output light of the EOM 160 C is changed, the fiber amplifiers 168 n and 17 1 the input light intensity is changed in n, resulting fiber amplifier 1 68 n, 1 7 pulsed light peak power of output from the 1 n is because sometimes changes. fiber amplifier 1 68 n, 1 7 1 By properly designing „, it is possible to suppress this peak power change, but it may reduce other performances such as the optical output efficiency of the fiber amplifier.
そこで、 本実施形態では、 予めファイバ増幅器出力の入力周波数強度依存性 を測定し、 それに基づいて光増幅部 1 6 1に入力するパルス光の周波数に応じ た光増幅部 1 6 1 (の各チャネル) の出力強度のマップである第 2の出力強度 マップ (EOMの出力光の周波数に対応した光増幅部 1 6 1の出力強度の換算 表) を作成し、 その第 2の出力強度マップをメモリ 5 1に記憶している。  Therefore, in the present embodiment, the input frequency intensity dependence of the fiber amplifier output is measured in advance, and based on the measured value, each channel of the optical amplifier 161 (corresponding to the frequency of the pulse light input to the optical amplifier 161) Create a second output intensity map (a conversion table of the output intensity of the optical amplifier 161, corresponding to the frequency of the output light of the EOM), which is a map of the output intensity of the EOM, and store the second output intensity map in the memory. 5 Memorized in 1.
そして、光量制御装置 1 6 Cでは、本第 2の機能により光量制御を行う際に、 主制御装置 50から与えられる設定光量と上記の第 2の出力強度マップとに基 づいて光量制御を行うようになっている。  Then, when performing the light amount control by the second function, the light amount control device 16C performs the light amount control based on the set light amount given from the main control device 50 and the above-mentioned second output intensity map. It has become.
また、 光量制御装置 1 6 Cは、 上記第 3の機能における EOM 1 60 Cから 出力されるパルス光のピークパワーの制御を、 EOM 1 60 Cへ印加する電圧 パルスのピーク強度を制御することにより行う。 EOM 1 60 Cの出力光のピ ークパワーは EOM 1 60 Cに印加する電圧パルスのピーク強度に依存するた めである。 The light amount control device 16C controls the peak power of the pulse light output from the EOM 160 C in the third function by controlling the peak intensity of the voltage pulse applied to the EOM 160 C. Do. The peak power of the output light of EOM 160 C depends on the peak intensity of the voltage pulse applied to EOM 160 C. It is.
また、 本実施形態では、 光増幅部 1 6 1の各チャネルの出力光の波長変換を 行う波長変換部 1 6 3が設けられているが、 この波長変換部 1 6 3の出力光強 度は、 各光ファイバ (光経路 1 7 2 n) から出力されるパルス光のピーク強度に 対し、最高では高調波の次数のべき乗に比例した非線形の依存を示す。例えば、 図 6 Aの 8倍波発生による 1 9 3 n m光発生では、 1 9 3 n m光出力強度はフ アイバ増幅器出力のピークパワーの最大で 8乗に比例した強度変化を示す。 本実施形態の場合、 E O M 1 6 0 Cから出力されるパルス光のピークパワー の E O M 1 6 0 Cに印加する電圧パルスのピーク強度に対する依存性は、 c 0 s ( V ) であるため、 結果的に上記の波長変換部 1 6 3の非線形な依存性は緩 和されるようになっている。 従って、 本実施形態のように波長変換部を有する 光源装置では、 出力光の強度 (光量) 制御を E O M 1 6 0 Cへ印加する電圧パ ルスのピーク強度を制御することによリ行うことは意味がある。 Further, in the present embodiment, the wavelength conversion section 163 for performing wavelength conversion of the output light of each channel of the optical amplification section 161 is provided, but the output light intensity of the wavelength conversion section 163 is The peak intensity of the pulsed light output from each optical fiber (optical path 1 72 n ) exhibits a nonlinear dependence that is at most proportional to the power of the harmonic order. For example, in the case of 19.3 nm light generation by 8th harmonic generation in Fig. 6A, the 193 nm light output intensity shows a change in intensity that is proportional to the eighth power at the maximum of the peak power of the fiber amplifier output. In the case of the present embodiment, the dependency of the peak power of the pulse light output from the EOM 160 C on the peak intensity of the voltage pulse applied to the EOM 160 C is c 0 s (V). Therefore, the nonlinear dependence of the wavelength conversion section 163 is moderated. Therefore, in the light source device having the wavelength conversion unit as in the present embodiment, it is not possible to control the intensity (light amount) of the output light by controlling the peak intensity of the voltage pulse applied to the EOM160C. It makes sense.
但し、 前述の如く、 ファイバ増幅器の増幅利得は、 入力光強度依存性がある ため、 E O M 1 6 0 Cから出力されるパルス光のピーク強度を変えると、 ファ ィバ増幅器 1 6 8 n、 1 7 1 nの入力光強度が変化し、 その結果ファイバ増幅器 1 6 8 n、 1 7 1 nから出力されるパルス光のピークパワーが変化する場合があ る。 ファイバ増幅器 1 6 8 n、 1 7 1 nを適切に設計することによリ、 このピー クパワー変化を小さく抑えることも可能ではあるが、 フアイバ増幅器の光出力 効率等の他の性能を低下させる場合もある。 However, as described above, the amplification gain of the fiber amplifier depends on the input light intensity. Therefore, if the peak intensity of the pulse light output from the EOM 160 C is changed, the fiber amplifiers 168 n , 1 7 1 n input light intensity is changed, there Ru if the result fiber amplifier 1 6 8 n, 1 7 peak power of the outputted pulse light from 1 n is changed. Fiber amplifier 1 6 8 n, 1 7 1 n properly by the designing Li case, although it is possible to suppress the peak Kupawa change, reducing the other performance such as the light output efficiency of the fiber amplifier There is also.
そこで、 本実施形態では、 予めファイバ増幅器出力の入力パルスピーク強度 依存性を測定し、 それに基づいて光増幅部 1 6 1に入力するパルス光のピーク 強度に対応した光増幅部 1 6 1 (の各チャネル) の出力強度のマップである第 3の出力強度マップ (E O Mの出力光のピーク強度に対応した光増幅部 1 6 1 の出力パルス光の強度の換算表) を作成し、 その第 3の出力強度マップをメモ リ 5 1に記憶している。 この第 3の出力強度マップは波長変換部出力である紫 外光強度マップであっても良い。 Therefore, in the present embodiment, the dependence of the output of the fiber amplifier on the input pulse peak intensity is measured in advance, and based on the measured value, the optical amplification unit 16 1 corresponding to the peak intensity of the pulse light input to the optical amplifier 16 A third output intensity map (a conversion table of the intensity of the output pulse light of the optical amplifier unit 161 corresponding to the peak intensity of the output light of the EOM), which is a map of the output intensity of each channel, is created. The output intensity map is stored in the memory 51. This third output intensity map is a purple It may be an external light intensity map.
そして、光量制御装置 1 6 Cでは、本第 3の機能により光量制御を行う際に、 主制御装置 5 0から与えられる設定光量と上記の第 3の出力強度マップとに基 づいて光量制御を行うようになっている。  Then, when performing the light amount control by the third function, the light amount control device 16C performs the light amount control based on the set light amount given from the main control device 50 and the third output intensity map. It is supposed to do.
なお、 D F B半導体レーザ 1 6 0 Aの出力段に、 E O M 1 6 0 Cの他に透過 率制御用の E 0 Mを設け、 この E 0 Mに印加する電圧を変化させることによリ その E O Mの透過率を変化させて、 単位時間あたりの光増幅部、 波長変換部か らの放出エネルギを変えることも可能である。  In addition, in addition to the EOM 160 C, an E 0 M for transmittance control is provided at the output stage of the DFB semiconductor laser 160 A, and the EOM is changed by changing the voltage applied to the E 0 M. It is also possible to change the emission energy from the optical amplification unit and wavelength conversion unit per unit time by changing the transmittance of the light.
これまでの説明から明らかなように、 光量制御装置 1 6 Cによる第 2、 第 3 の機能では、 第 1の機能に比べて、 より細やかな光源装置 1 6の出力光の光量 制御が可能である。 一方、 第 1の機能は、 第 2、 第 3の機能に比べて、 ダイナ ミックレンジを広く設定することが可能である。  As is clear from the above description, the second and third functions of the light amount control device 16C can control the light amount of the output light of the light source device 16 more finely than the first function. is there. On the other hand, the first function can set a wider dynamic range than the second and third functions.
そこで、 本実施形態では、 後述する露光に際して、 光量制御装置 1 6 Cの上 記第 1の機能により露光量の粗調整を行い、 第 2、 第 3の機能を用いて露光量 の微調整を行うようになっている。 これについては、 後述する。  Therefore, in the present embodiment, at the time of exposure to be described later, coarse adjustment of the exposure amount is performed by the first function of the light amount control device 16C, and fine adjustment of the exposure amount is performed by using the second and third functions. It is supposed to do. This will be described later.
光量制御装置 1 6 Cは、 この他、 主制御装置 5 0からの指示に基づいてパル ス出力の開始と停止なども制御する。  The light amount control device 16C also controls the start and stop of the pulse output based on an instruction from the main control device 50.
前記偏光調整装置 1 6 Dは、 光ファイバ増幅器 1 7 l nよりも前段の光部品 の偏光特性を制御することにより、 光ファイバ増幅器 1 7 1 nから射出される 光を円偏光化する。 なお、 光ファイバ増幅器 1 7 1 nのドープ ·ファイバがほ ぼ円筒対称な構造を有しており、 かつ、 比較的短い場合には、 光ファイバ増幅 器 1 7 1 nに入射する光を円偏光化することによつても、 光ファイバ増幅器 1 7 1 nから射出される光を円偏光化することができる。 The polarization adjustment device 1 6 D, by than the optical fiber amplifier 1 7 l n for controlling the polarization characteristics of the front side of the optical component, to circularly polarized light of the light emitted from the optical fiber amplifier 1 7 1 n. If the doped fiber of the optical fiber amplifier 171 n has a substantially cylindrically symmetric structure and is relatively short, the light incident on the optical fiber amplifier 171 n is circularly polarized. Also, the light emitted from the optical fiber amplifier 17 1 n can be circularly polarized.
ここで、 光ファイバ増幅器 1 7 1 nよりも前段の光部品には、 上述した光増 幅部 1 6 1の各要素を光学的に結合するための不図示のリレー光ファイバ等が ある。 こうしたリレー光ファイバ等の偏光特性の制御方法としては、 例えばリ レー光フアイバに非等方的な力学的ス卜レスを加える方法があり、 本実施形態 でもこの方法を採用している。 Here, the front side of the optical component than the optical fiber amplifier 1 7 1 n may relay optical fiber or the like (not shown) for coupling the elements of the optical amplification section 1 6 1 described above optically. Methods for controlling the polarization characteristics of such relay optical fibers include, for example, There is a method of adding anisotropic mechanical stress to the ray fiber, and this method is also employed in the present embodiment.
一般に、 リレー光ファイバは円筒対称な屈折率分布を有しているが、 非等方 的な力学的ス卜レスが加わると非等方的な応力がリレー光ファイバに発生し、 この応力により非等方的な屈折率分布が生じる。 こうした非等方的な屈折率分 布の発生量を制御することによって、 リレー光ファイバの偏光特性を制御する ことができる。  Generally, a relay optical fiber has a refractive index distribution that is cylindrically symmetric. However, when an anisotropic mechanical stress is applied, an anisotropic stress is generated in the relay optical fiber. An isotropic refractive index distribution occurs. By controlling the amount of such anisotropic refractive index distribution, the polarization characteristics of the relay optical fiber can be controlled.
また、 リレー光ファイバの応力による屈折率分布の変化量や他の光部品の偏 光特性は一般に温度に依存している。 このため、 偏光調整装置 1 6 Dは、 リレ 一光ファイバ等の周囲温度を一定とする温度制御を行って、 一度行った円偏光 化が維持可能としている。  Also, the amount of change in the refractive index distribution due to the stress of the relay optical fiber and the polarization characteristics of other optical components generally depend on temperature. For this reason, the polarization adjusting device 16D performs temperature control to keep the ambient temperature of the relay optical fiber or the like constant so that the circular polarization once performed can be maintained.
なお、 上記の温度制御を行わずに、 リレー光ファイバよりも下流側のいずれ かの位置で光の偏光状態のモニタを行い、 このモニタ結果に基づいて、 リレー 光ファイバの偏光特性すなわち屈折率分布を制御してもよい。  In addition, without performing the temperature control described above, the polarization state of light is monitored at any position downstream of the relay optical fiber, and based on the monitoring result, the polarization characteristics of the relay optical fiber, that is, the refractive index distribution. May be controlled.
図 1に戻り、 前記照明光学系 1 2は、 ビーム整形光学系 1 8、 オプティカル インテグレータ (ホモジナイザ) としてのフライアイレンズ系 2 2、 照明系開 口絞り板 2 4、 ビームスプリッタ 2 6、 第 1 リレーレンズ 2 8 A、 第 2リレー レンズ 2 8 B、 固定レチクルブラインド 3 0 A、 可動レチクルブラインド 3 0 B、 光路折り曲げ用のミラー M及びコンデンサレンズ 3 2等を備えている。 前記ビーム整形光学系 1 8は、 光源装置 1 6の波長変換部 1 6 3の波長変換 により発生した紫外域の光、 (以下、 「レーザビーム」 と呼ぶ) L Bの断面形状 を、 該レーザビーム L Bの光路後方に設けられたフライアイレンズ系 2 2に効 率良く入射するように整形するもので、 例えばシリンダレンズやビームエキス パンダ (いずれも図示省略) 等で構成される。  Returning to FIG. 1, the illumination optical system 12 includes a beam shaping optical system 18, a fly-eye lens system 22 as an optical integrator (homogenizer), an illumination system aperture stop plate 24, a beam splitter 26, and a first optical system. It has a relay lens 28A, a second relay lens 28B, a fixed reticle blind 30A, a movable reticle blind 30B, a mirror M for bending the optical path, and a condenser lens 32. The beam shaping optical system 18 converts the cross-sectional shape of the LB (hereinafter referred to as “laser beam”) generated by the wavelength conversion of the wavelength conversion unit 16 3 of the light source device 16 into the laser beam. It is shaped so as to efficiently enter the fly-eye lens system 22 provided behind the LB optical path, and includes, for example, a cylinder lens and a beam expander (both not shown).
前記フライアイレンズ系 2 2は、 ビーム整形光学系 1 8から出たレーザビー 厶 L Bの光路上に配置され、 レチクル Rを均一な照度分布で照明するために多 数の光源像からなる面光源、 即ち 2次光源を形成する。 この 2次光源から射出 されるレーザビームを本明細書においては、 「露光光 I L」 とも呼んでいる。 フライアイレンズ系 2 2の射出面の近傍に、 円板状部材から成る照明系開口 絞り板 2 4が配置されている。この照明系開口絞り板 2 4には、等角度間隔で、 例えば通常の円形開口より成る開口絞り、 小さな円形開口より成リコヒーレン スファクタである σ値を小さくするための開口絞り、 輪帯照明用の輪帯状の開 口絞り、 及び変形光源法用に複数の開口を偏心させて配置して成る変形開口絞 り (図 1ではこのうちの 2種類の開口絞りのみが図示されている) 等が配置さ れている。 この照明系開口絞り板 2 4は、 主制御装置 5 0により制御されるモ 一夕等の駆動装置 4ひにより回転されるようになっており、 これによりレチク ルパターンに応じていずれかの開口絞りが露光光 I Lの光路上に選択的に設定 される。 The fly-eye lens system 22 is arranged on the optical path of the laser beam LB emitted from the beam shaping optical system 18 and is used to illuminate the reticle R with a uniform illuminance distribution. Form a surface light source consisting of a number of light source images, that is, a secondary light source. The laser beam emitted from the secondary light source is also referred to as “exposure light IL” in this specification. An illumination system aperture stop plate 24 made of a disc-shaped member is arranged near the exit surface of the fly-eye lens system 22. This illumination system aperture stop plate 24 is provided at equal angular intervals, for example, an aperture stop composed of a normal circular aperture, an aperture stop for reducing the σ value, which is a lithocoherence factor, compared to a small circular aperture, and an annular aperture. A ring-shaped aperture stop, a modified aperture stop with multiple apertures eccentrically arranged for the modified light source method (only two of these apertures are shown in Fig. 1), etc. Has been done. The illumination system aperture stop plate 24 is configured to be rotated by a drive unit 4 such as a motor controlled by a main controller 50 so that any one of the apertures can be selected according to the reticle pattern. The aperture is selectively set on the optical path of the exposure light IL.
照明系開口絞り板 2 4から出た露光光 I しの光路上に、 反射率が小さく透過 率の大きなビー厶スプリツ夕 2 6が配置され、 更にこの後方の光路上に、 固定 レチクルプラインド 3 O A及び可動レチクルブラインド 3 0 Bを介在させて第 1 リレーレンズ 2 8 A及び第 2リレーレンズ 2 8 Bから成るリレー光学系が配 置されている。  A beam splitter 26 having a small reflectance and a large transmittance is arranged on the optical path of the exposure light I coming out of the illumination system aperture stop plate 24, and a fixed reticle blind 3 is provided on the optical path behind this. A relay optical system including a first relay lens 28A and a second relay lens 28B is provided with an OA and a movable reticle blind 30B interposed therebetween.
固定レチクルブラインド 3 0 Aは、 レチクル Rのパターン面に対する共役面 から僅かにデフォーカスした面に配置され、 レチクル R上の照明領域 4 2 Rを 規定する矩形開口が形成されている。 また、 この固定レチクルブラインド 3 0 Aの近傍に走査方向の位置及び幅が可変の開口部を有する可動レチクルブライ ンド 3 0 Bが配置され、 走査露光の開始時及び終了時にその可動レチクルブラ インド 3 0 Bを介して照明領域 4 2 Rを更に制限することによって、 不要な部 分の露光が防止されるようになつている。  The fixed reticle blind 30A is disposed on a plane slightly defocused from a conjugate plane with respect to the pattern plane of the reticle R, and has a rectangular opening defining an illumination area 42R on the reticle R. A movable reticle blind 30B having an opening whose position and width in the scanning direction is variable is arranged near the fixed reticle blind 30A, and the movable reticle blind 30B is provided at the start and end of scanning exposure. By further restricting the illumination area 42R via B, unnecessary portions of the exposure are prevented.
リレー光学系を構成する第 2リレーレンズ 2 8 B後方の露光光 I Lの光路上 には、 当該第 2リレーレンズ 2 8 Bを通過した露光光 I Lをレチクル Rに向け て反射する折り曲げミラー Mが配置され、 このミラー M後方の露光光 I しの光 路上にコンデンサレンズ 3 2が配置されている。 On the optical path of the exposure light IL behind the second relay lens 28 B constituting the relay optical system, the exposure light IL passing through the second relay lens 28 B is directed toward the reticle R. A bending mirror M that reflects light is disposed, and a condenser lens 32 is disposed on the optical path of the exposure light I behind the mirror M.
更に、 照明光学系 1 2内のビームスプリッタ 2 6で垂直に折り曲げられる一 方の光路上、 他方の光路上には、 インテグレー夕センサ 4 6、 反射光モニタ 4 7がそれぞれ配置されている。 これらインテグレー夕センサ 4 6、 反射光モニ タ 4 7としては、 遠紫外域及び真空紫外域で感度が良く、 且つ光源装置 1 6の パルス発光を検出するために高い応答周波数を有する S i系 P I N型フ才卜ダ ィオードが用いられている。 なお、 インテグレータセンサ 4 6、 反射光モニタ 4 7として G a N系結晶を有する半導体受光素子を用いることも可能である。 以上の構成において、 フライアイレンズ系 2 2の入射面、 可動レチクルブラ インド 3 0 Bの配置面、 レチクル Rのパターン面は、 光学的に互いに共役に設 定され、 フライアイレンズ系 2 2の射出面側に形成される光源面、 投影光学系 P Lのフーリエ変換面 (射出瞳面) は光学的に互いに共役に設定され、 ケーラ 一照明系となっている。  Furthermore, an integrator sensor 46 and a reflected light monitor 47 are arranged on one of the optical paths that are bent vertically by the beam splitter 26 in the illumination optical system 12 and on the other optical path. The integrator sensor 46 and the reflected light monitor 47 have high sensitivity in the deep ultraviolet region and the vacuum ultraviolet region and have a high response frequency for detecting the pulse light emission of the light source device 16. A type diode is used. Note that a semiconductor light-receiving element having a GaN-based crystal can also be used as the integrator sensor 46 and the reflected light monitor 47. In the above configuration, the entrance surface of the fly-eye lens system 22, the arrangement surface of the movable reticle blind 30 B, and the pattern surface of the reticle R are optically set to be conjugate with each other, and the emission of the fly-eye lens system 22 is performed. The light source surface formed on the surface side and the Fourier transform plane (exit pupil plane) of the projection optical system PL are optically set to be conjugate to each other, and form a Koehler-single illumination system.
このようにして構成された照明光学系 1 2の作用を簡単に説明すると、 光源 装置 1 6からパルス発光されたレーザビーム L Bは、 ビーム整形光学系 1 8に 入射して、 ここで後方のフライアイレンズ系 2 2に効率良く入射するようにそ の断面形状が整形された後、フライアイレンズ系 2 2に入射する。これにより、 フライアイレンズ系 2 2の射出側焦点面 (照明光学系 1 2の瞳面) に 2次光源 が形成される。 この 2次光源から射出された露光光 I Lは、 照明系開口絞り板 2 4上のいずれかの開口絞りを通過した後、 透過率が大きく反射率が小さなビ —ムスプリッタ 2 6に至る。 このビームスプリッタ 2 6を透過した露光光 I L は、 第 1 リレーレンズ 2 8 Aを経て固定レチクルブラインド 3 0 Aの矩形の開 口部及び可動レチクルブラインド 3 0 Bを通過した後、 第 2リレーレンズ 2 8 Bを通過してミラー Mによって光路が垂直下方に折り曲げられた後、 コンデン サレンズ 3 2を経て、 レチクルステージ R S T上に保持されたレチクル R上の 矩形の照明領域 4 2 Rを均一な照度分布で照明する。 The operation of the illumination optical system 12 configured as described above will be briefly described. A laser beam LB pulsed from the light source device 16 is incident on the beam shaping optical system 18, where the laser beam LB at the rear is formed. After its cross-sectional shape is shaped so as to efficiently enter the eye lens system 22, the light enters the fly-eye lens system 22. As a result, a secondary light source is formed on the exit-side focal plane of the fly-eye lens system 22 (the pupil plane of the illumination optical system 12). The exposure light IL emitted from the secondary light source passes through one of the aperture stops on the illumination system aperture stop plate 24 and then reaches a beam splitter 26 having a large transmittance and a small reflectance. Exposure light IL transmitted through the beam splitter 26 passes through the first relay lens 28 A, passes through the rectangular opening of the fixed reticle blind 30 A and the movable reticle blind 30 B, and then passes through the second relay lens. After passing through 28B, the optical path is bent vertically downward by the mirror M, and then passes through the condenser lens 32, on the reticle R held on the reticle stage RST. The rectangular illumination area 42R is illuminated with a uniform illuminance distribution.
一方、 ビームスプリッタ 2 6で反射された露光光 I Lは、 集光レンズ 4 4を 介してインテグレータセンサ 4 6で受光され、 インテグレータセンサ 4 6の光 電変換信号が、 不図示のピークホールド回路及び A Z D変換器を介して出力 D S (d igi t/pul se)として主制御装置 5 0に供給される。 このインテグレータセ ンサ 4 6の出力 D Sと、 ウェハ Wの表面上での露光光 I しの照度 (露光量) と の相関係数は、 予め求められ、 主制御装置 5 0に併設された記憶装置としての メモリ 5 1内に記憶されている。  On the other hand, the exposure light IL reflected by the beam splitter 26 is received by the integrator sensor 46 via the condenser lens 44, and the photoelectric conversion signal of the integrator sensor 46 is converted to a peak hold circuit (not shown) and an AZD. It is supplied to the main controller 50 as an output DS (digital / pulse) via a converter. The correlation coefficient between the output DS of the integrator sensor 46 and the illuminance (exposure amount) of the exposure light I on the surface of the wafer W is obtained in advance, and the storage device provided in the main controller 50 is provided. As stored in memory 51.
また、レチクル R上の照明領域 4 2 Rを照明しそのレチクルのパターン面(図 1における下面) で反射された反射光束は、 コンデンサレンズ 3 2、 リレー光 学系を前と逆向きに通過し、 ビームスプリッタ 2 6で反射され、 集光レンズ 4 8を介して反射光モニタ 4 7で受光される。 また、 Zチル卜ステージ 5 8が投 影光学系 P Lの下方にある場合には、 レチクルのパターン面を透過した露光光 I Lは、 投影光学系 P L及びウェハ Wの表面 (あるいは後述する基準マーク板 F M表面) で反射され、 その反射光束は、 投影光学系 Pし、 レチクル R、 コン デンサレンズ 3 2、 リレー光学系を前と逆向きに順次通過し、 ビー厶スプリツ タ 2 6で反射され、 集光レンズ 4 8を介して反射光モニタ 4 7で受光される。 また、 ビームスプリッタ 2 6とウェハ Wとの間に配置される各光学素子はその 表面に反射防止膜が形成されているものの、 その表面で露光光 I Lがわずかに 反射され、 これら反射光も反射光モニタ 4 7で受光される。 この反射光モニタ 4 7の光電変換信号が、 不図示のピークホールド回路及び A Z D変換器を介し て主制御装置 5 0に供給される。 反射光モニタ 4 7は、 本実施形態では、 主と してウェハ Wの反射率の測定等に用いられる。なお、この反射光モニタ 4 7を、 レチクル Rの透過率の事前測定の際に用いても良い。  The illuminated area 42 R on the reticle R illuminates and the reflected light flux reflected on the pattern surface of the reticle (the lower surface in Fig. 1) passes through the condenser lens 32 and the relay optical system in the opposite direction to the front. The light is reflected by the beam splitter 26 and received by the reflected light monitor 47 via the condenser lens 48. When the Z tilt stage 58 is below the projection optical system PL, the exposure light IL transmitted through the pattern surface of the reticle is applied to the projection optical system PL and the surface of the wafer W (or a reference mark plate described later). The reflected light flux passes through the projection optical system P, passes through the reticle R, the condenser lens 32, and the relay optical system in the reverse direction, and is reflected by the beam splitter 26. The reflected light is received by the reflected light monitor 47 via the optical lens 48. In addition, although each optical element disposed between the beam splitter 26 and the wafer W has an anti-reflection film formed on its surface, the exposure light IL is slightly reflected on its surface, and these reflected lights are also reflected. The light is received by the optical monitor 47. The photoelectric conversion signal of the reflected light monitor 47 is supplied to the main controller 50 via a peak hold circuit (not shown) and an AZD converter. In this embodiment, the reflected light monitor 47 is mainly used for measuring the reflectance of the wafer W. Note that the reflected light monitor 47 may be used for the preliminary measurement of the transmittance of the reticle R.
なお、 フライアイレンズ系として、 例えば特開平 1一 2 3 5 2 8 9号公報及 びこれに対応する米国特許第 5 , 3 0 7, 2 0 7号、 特開平 7— 1 4 2 3 5 4 号公報及びこれに対応する米国特許第 5, 5 3 4 , 9 7 0号などに開示される ダブルフライアイレンズ系を採用し、 ケーラー照明系を構成しても良い。 本国 際出願で指定した指定国又は選択した選択国の国内法令が許す限りにおいて、 上記各公報並びにこれらに対応する上記各米国特許における開示を援用して本 明細書の記載の一部とする。 As a fly-eye lens system, for example, Japanese Patent Application Laid-Open No. Hei 11-235289 and US Patent No. 5,307,207 corresponding thereto, Japanese Patent Application Laid-Open No. The double fly-eye lens system disclosed in, for example, Japanese Patent Application Laid-Open Publication No. Heisei 5 and corresponding US Pat. No. 5,534,970, etc. may be adopted to constitute a Koehler illumination system. To the extent permitted by the national laws of the designated or designated elected country in the international application, the disclosures in each of the aforementioned gazettes and corresponding US patents are incorporated herein by reference to constitute a part of the description of this specification.
また、フライアイレンズ系 2 2とともに、回折光学素子(di ifract ive opt ical element)を用いても良い。 かかる回折光学素子を用いる場合には、光源装置 1 6と照明光学系 1 2とを回折光学素子を介して接続するようにしても良い。 すなわち、 バンドル一ファイバの各ファイバに対応して回折素子が形成され る回折光学素子をビーム整形光学系 1 8に設け、 各ファイバから出力されるレ 一ザビームを回折させて、 フライアイレンズ系 2 2の入射面上で重畳させるよ うにしても良い。 本実施形態では、 バンドル一ファイバの出力端を照明光学系 の瞳面に配置しても良いが、 この場合には第 1の機能 (間引き) によってその 瞳面上での強度分布 (即ち 2次光源の形状や大きさなど) が変化することにな り、 レチクルパターンに最適な形状、 大きさとは異なってしまうことがある。 そこで、 前述の回折光学素子などを用いて照明光学系の瞳面、 又は才プティカ ルインテグレー夕の入射面上で各ファイバからのレーザビームを重畳させるよ うにすることが望ましい。  In addition, a diffractive optical element may be used together with the fly-eye lens system 22. When such a diffractive optical element is used, the light source device 16 and the illumination optical system 12 may be connected via a diffractive optical element. That is, a diffractive optical element in which a diffractive element is formed corresponding to each fiber of a bundle fiber is provided in the beam shaping optical system 18, and a laser beam output from each fiber is diffracted to form a fly-eye lens system 2. It may be superimposed on the incident surface of No. 2. In the present embodiment, the output end of the bundle-one fiber may be arranged on the pupil plane of the illumination optical system. In this case, however, the first function (decimation) causes the intensity distribution on the pupil plane (ie, the secondary The shape and size of the light source), which may differ from the optimal shape and size for the reticle pattern. Therefore, it is desirable to superimpose the laser beam from each fiber on the pupil plane of the illumination optical system or the entrance plane of the optical integrator using the above-described diffractive optical element.
いずれにしても、 本実施形態では、 前述した光量制御装置 1 6 Cの第 1の機 能によりバンドル一ファイバ 1 7 3の光を出力する部分の分布が変化した場合 であっても、 レチクル Rのパターン面 (物体面) 上及びウェハ Wの面 (像面) 上のいずれにおいても照度分布の均一性を十分に確保することができる。  In any case, in the present embodiment, even if the distribution of the light output portion of the bundle-one fiber 1 73 changes due to the first function of the light amount control device 16 C described above, the reticle R The uniformity of the illuminance distribution can be sufficiently ensured on both the pattern surface (object surface) and the surface (image surface) of the wafer W.
前記レチクルステージ R S T上にレチクル Rが載置され、 不図示のバキュー 厶チャック等を介して吸着保持されている。 レチクルステージ R S Tは、 水平 面 (X Y平面) 内で微小駆動可能であるとともに、 レチクルステージ駆動部 4 9によって走査方向 (ここでは図 1の紙面左右方向である Y方向とする) に所 定ス卜ローク範囲で走査されるようになっている。 この走査中のレチクルステ ージ R S Tの位置及び回転量は、 レチクルステージ R S T上に固定された移動 鏡 5 2 Rを介して外部のレーザ干渉計 5 4 Rによって計測され、 このレーザ干 渉計 5 4 Rの計測値が主制御装置 5 0に供給されるようになっている。 A reticle R is mounted on the reticle stage RST, and is held by suction via a vacuum chuck (not shown). The reticle stage RST can be finely driven in a horizontal plane (XY plane), and is moved in the scanning direction (here, the Y direction, which is the horizontal direction in FIG. 1) by a reticle stage driving unit 49. Scanning is performed within a fixed stroke range. The position and the rotation amount of the reticle stage RST during this scanning are measured by an external laser interferometer 54 R via a movable mirror 52 R fixed on the reticle stage RST, and the laser interferometer 54 The measured value of R is supplied to the main controller 50.
なお、 レチクル Rに用いる材質は、 露光光 I Lの波長によって使い分ける必 要がある。 すなわち、 波長 1 9 3 n mの露光光を用いる場合には合成石英を用 いることができるが、 波長 1 5 7 n mの露光光を用いる場合は、 ホタル石、 フ ッ素がドープされた合成石英、 あるいは水晶などで形成する必要がある。 前記投影光学系 P Lは、 例えば両側テレセン卜リックな縮小系であり、 共通 の Z軸方向の光軸を有する複数枚のレンズエレメント 7 0 a、 7 0 b、 ……か ら構成されている。 また、 この投影光学系 P Lとしては、 投影倍率 )8が例えば 1 Z 4、 1 5、 1 6などのものが使用されている。 このため、 前記の如く して、 露光光 I しによリレチクル R上の照明領域 4 2 Rが照明されると、 その レチクル Rに形成されたパターンが投影光学系 P Lによつて投影倍率 βで縮小 された像が表面にレジス卜 (感光剤) が塗布されたウェハ W上のスリット状の 露光領域 4 2 Wに投影され転写される。  The material used for the reticle R needs to be properly used depending on the wavelength of the exposure light IL. That is, when using exposure light with a wavelength of 193 nm, synthetic quartz can be used, but when using exposure light with a wavelength of 157 nm, synthetic quartz doped with fluorite or fluorine is used. , Or must be formed of quartz or the like. The projection optical system P L is, for example, a telecentric reduction system on both sides, and is composed of a plurality of lens elements 70 a, 70 b,... Having a common optical axis in the Z-axis direction. Further, as the projection optical system PL, one having a projection magnification) 8 of, for example, 1Z4, 15 or 16 is used. Therefore, as described above, when the illumination area 42 R on the reticle R is illuminated by the exposure light I, the pattern formed on the reticle R is projected by the projection optical system PL at a projection magnification β. The reduced image is projected and transferred to a slit-shaped exposure area 42 W on a wafer W having a resist (photosensitive agent) applied on the surface.
本実施形態では、 上記のレンズエレメントのうち、 複数のレンズエレメント がそれぞれ独立に移動可能となっている。 例えば、 レチクルステージ R S丁に 最も近い一番上のレンズエレメント 7 0 aは、 リング状の支持部材 7 2により 保持され、 この支持部材 7 2は、 伸縮可能な駆動素子、 例えばピエゾ素子 7 4 a, 7 4 b , 7 4 c (紙面奥側の駆動素子 7 4 cは図示せず) によって、 3点 支持されるとともに鏡筒部 7 6と連結されている。 上記の駆動素子 7 4 a, 7 4 b , 7 4 cによって、 レンズエレメント 7 0 aの周辺 3点を独立に、 投影光 学系 P Lの光軸 A X方向に移動させることができるようになつている。 すなわ ち、 レンズエレメント 7 0 aを駆動素子 7 4 a, 7 4 b , 7 4 cの変位量に応 じて光軸 A Xに沿って平行移動させることができるとともに、 光軸 A Xと垂直 な平面に対して任意に傾斜させることもできる。 そして、 これらの駆動素子 7 4 a , 7 4 b , 7 4 cに与えられる電圧が、 主制御装置 5 0からの指令に基づ いて結像特性補正コントローラ 7 8によって制御され、 これによつて駆動素子 7 4 a , 7 4 b , 7 4 cの変位量が制御されるようになっている。 なお、 図 1 中、 投影光学系 P Lの光軸 A Xとは鏡筒部 7 6に固定されているレンズエレメ ン卜 7 0 bその他のレンズエレメント (図示省略) の光軸を指す。 In the present embodiment, among the above lens elements, a plurality of lens elements are independently movable. For example, the uppermost lens element 70a closest to the reticle stage RS is held by a ring-shaped support member 72. This support member 72 is a telescopic drive element, for example, a piezo element 74a. , 74 b, 74 c (the drive element 74 c on the back side of the drawing is not shown), and is supported at three points and connected to the lens barrel 76. The driving elements 74a, 74b, and 74c allow the three points around the lens element 70a to be independently moved in the optical axis AX direction of the projection optical system PL. I have. That is, the lens element 70a can be translated along the optical axis AX according to the displacement of the driving elements 74a, 74b, and 74c, and can be moved perpendicularly to the optical axis AX. It can also be arbitrarily inclined with respect to a simple plane. The voltages applied to these drive elements 74 a, 74 b, and 74 c are controlled by the imaging characteristic correction controller 78 based on a command from the main controller 50, whereby The displacement amounts of the drive elements 74a, 74b, and 74c are controlled. In FIG. 1, the optical axis AX of the projection optical system PL refers to the optical axis of the lens element 70 b fixed to the lens barrel 76 and other lens elements (not shown).
また、 本実施形態では、 予め実験によりレンズエレメント 7 0 aの上下量と 倍率 (又はディストーション) の変化量との関係を求めておき、 これを例えば メモリ 5 1に記憶しておき、 補正時に主制御装置 5 0が補正する倍率 (又はデ イス! ^一シヨン) からレンズエレメント 7 0 aの上下量を計算し、 結像特性補 正コントローラ 7 8に指示を与えて駆動素子 7 4 a, 7 4 b , 7 4 cを駆動す ることにより倍率 (又はデイス! ^一シヨン) 補正を行うようになっている。 す なわち、 本実施形態では、 結像特性補正コントローラ 7 8、 駆動素子 7 4 a, 7 4 b , 7 4 c、 及び主制御装置 5 0によって、 投影光学系 P Lの結像特性を 補正する結像特性補正装置が構成されている。  Further, in the present embodiment, the relationship between the vertical amount of the lens element 70a and the change amount of the magnification (or distortion) is obtained in advance by an experiment, and this is stored in, for example, the memory 51, and the correction is mainly performed. The controller 50 calculates the vertical amount of the lens element 70a from the magnification (or device! ^ 1) corrected by the controller 50, and gives instructions to the imaging characteristic correction controller 78 to drive the drive elements 74a, 7a. By driving 4b and 74c, magnification (or day! ^ 1) correction is performed. That is, in the present embodiment, the imaging characteristic of the projection optical system PL is corrected by the imaging characteristic correction controller 78, the driving elements 74a, 74b, 74c, and the main controller 50. An imaging characteristic correction device is configured.
なお、 前記レンズエレメント 7 0 aの上下量と倍率等の変化量との関係は光 学的な計算値を用いてもよく、 この場合は前記レンズエレメント 7 0 aの上下 量と倍率変化量との関係を求める実験の工程が省けることになる。  The relationship between the vertical amount of the lens element 70a and the amount of change in magnification or the like may use an optically calculated value. In this case, the vertical amount of the lens element 70a and the amount of change in magnification may be used. The experiment process for finding the relationship can be omitted.
前記の如く、 レチクル Rに最も近いレンズエレメント 7 0 aが移動可能とな つているが、 このエレメント 7 0 aは倍率、 デイス! ^一シヨン特性に与える影 響が他のレンズェレメン卜に比べて大きく制御しゃすいものの 1つを選択した ものであって、 同様の条件を満たすものであれば、 このレンズエレメント 7 0 aに代えてどのレンズエレメントをレンズ間隔調整のために移動可能に構成し ても良い。  As described above, the lens element 70a closest to the reticle R is movable.However, this element 70a has a greater effect on magnification and distance! If one of the controls is selected and the same condition is satisfied, any lens element may be configured to be movable for adjusting the lens interval instead of the lens element 70a. good.
なお、 レンズエレメント 7 0 a以外の少なくとも 1つのレンズエレメントを 移動して他の光学特性、 例えば像面湾曲、 非点収差、 コマ収差、 又は球面収差 などを調整できるようになつている。 この他、 投影光学系 P Lの光軸方向中央 部近傍の特定のレンズエレメント相互間に密封室を設け、 この密封室内の気体 の圧力を例えばべローズポンプ等の圧力調整機構により調整することにより、 投影光学系 P Lの倍率を調整する結像特性補正機構を設けても良く、あるいは、 例えば、 投影光学系 P Lを構成する一部のレンズエレメン卜として非球面状レ ンズを用い、 これを回転させるようにしても良い。 この場合には、 いわゆるひ し形ディストーションの補正が可能になる。 あるいは、 投影光学系 P L内に平 行平面板を設け、 これをチル卜させたり、 回転させたりするような機構により 結像特性補正機構を構成しても良い。 It should be noted that at least one lens element other than the lens element 70a is moved to obtain other optical characteristics such as curvature of field, astigmatism, coma, or spherical aberration. And so on. In addition, a sealing chamber is provided between specific lens elements near the center of the projection optical system PL in the optical axis direction, and the pressure of gas in the sealing chamber is adjusted by a pressure adjusting mechanism such as a bellows pump. An imaging characteristic correction mechanism that adjusts the magnification of the projection optical system PL may be provided, or, for example, an aspherical lens is used as a part of the lens elements constituting the projection optical system PL, and this is rotated. You may do it. In this case, so-called rhombic distortion can be corrected. Alternatively, a parallel plane plate may be provided in the projection optical system PL, and the imaging characteristic correction mechanism may be configured by a mechanism that tilts or rotates the parallel flat plate.
なお、 露光光 I しとして波長 1 9 3 n mのレーザ光を用いる場合には、 投影 光学系 P Lを構成する各レンズエレメント (及び上記平行平面板) としては合 成石英ゃホタル石等を用いることができるが、 波長 1 5 7 n mのレーザ光を用 いる場合には、 この投影光学系 P Lに使用されるレンズ等の材質は、 全てホタ ル石が用いられる。  When a laser beam with a wavelength of 193 nm is used as the exposure light I, synthetic quartz / fluorite or the like should be used as each lens element (and the above-mentioned parallel flat plate) constituting the projection optical system PL. However, when laser light having a wavelength of 157 nm is used, fluorite is used for all materials such as lenses used in the projection optical system PL.
また、 本実施形態では、 チャンバ 1 1内の大気圧を測定する大気圧センサ 7 7が設けられている。 この大気圧センサ 7 7の計測値は、 主制御装置 5 0に供 給されるようになっており、 主制御装置 5 0では、 この大気圧センサ 7 7の計 測値に基づいて、 標準大気圧からの気圧の変動を算出するとともに、 投影光学 系 P Lの結像特性の大気圧変動を算出する。 そして、 この大気圧変動分を考慮 して結像特性補正コントローラ 7 8に指示を与えて、 投影光学系 P Lの結像特 性を補正する。  In the present embodiment, an atmospheric pressure sensor 77 that measures the atmospheric pressure in the chamber 11 is provided. The measured value of the atmospheric pressure sensor 77 is supplied to the main controller 50, and the main controller 50 uses the standard atmospheric pressure sensor 77 based on the measured value of the atmospheric pressure sensor 77. Calculate the fluctuation of the atmospheric pressure from the atmospheric pressure and the atmospheric pressure fluctuation of the imaging characteristics of the projection optical system PL. Then, an instruction is given to the imaging characteristic correction controller 78 in consideration of the variation in the atmospheric pressure to correct the imaging characteristic of the projection optical system PL.
なお、 上記の発振波長の変更は、 主制御装置 5 0から指示に基づき、 レーザ 制御装置 1 6 Bがビームモニタ機構 1 6 4を構成するエタロン素子の温度を積 極的に制御して、エタロン素子の透過率が最大となる共鳴波長(検出基準波長) がー致している設定波長 (目標波長) を変更すると共に、 この変更後の設定波 長に D F B半導体レーザ 1 6 O Aの発振波長が一致するように、 D F B半導体 レーザ 1 6 0 Aの温度をフィードバック制御することにより容易に達成される。 なお、 主制御装置 5 0による結像特性の大気圧変動分、 照射変動分等の演算 方法等については、 例えば特開平 9— 2 1 3 6 1 9号公報等に詳細に開示され ており、 公知であるから、 ここでは詳細な説明は省略する。 The above-mentioned change of the oscillation wavelength is performed by the laser controller 16B, based on an instruction from the main controller 50, by actively controlling the temperature of the etalon element constituting the beam monitor mechanism 164, and The set wavelength (target wavelength) at which the resonance wavelength (detection reference wavelength) at which the transmittance of the element is maximized is changed, and the oscillation wavelength of the DFB semiconductor laser 16 OA matches the changed set wavelength. As the DFB semiconductor This is easily achieved by feedback controlling the temperature of the laser 160A. The method of calculating the atmospheric pressure fluctuation, the irradiation fluctuation, and the like of the imaging characteristics by the main controller 50 is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 9-213139, Since it is publicly known, detailed description is omitted here.
前記 X Yステージ 1 4は、 ウェハステージ駆動部 5 6によって走査方向であ る Y方向及びこれに直交する X方向 (図 1における紙面直交方向) に 2次元駆 動されるようになっている。 この X Yステージ 1 4上に搭載された Zチル卜ス テージ 5 8上に不図示のウェハホルダを介してウェハ Wが真空吸着等により保 持されている。 Zチルトステージ 5 8は、 例えば 3つのァクチユエ一夕 (ピエ ゾ素子又はボイスコイルモータなど) によってウェハ Wの Z方向の位置 (フ才 一カス位置) を調整すると共に、 X Y平面 (投影光学系 P Lの像面) に対する ウェハ Wの傾斜角を調整する機能を有する。また、 X Yステージ 1 4の位置は、 Zチル卜ステージ 5 8上に固定された移動鏡 5 2 Wを介して外部のレーザ干渉 計 5 4 Wにより計測され、 このレーザ干渉計 5 4 Wの計測値が主制御装置 5 0 に供給されるようになっている。  The XY stage 14 is driven two-dimensionally by a wafer stage drive unit 56 in the Y direction, which is the scanning direction, and the X direction, which is orthogonal to the scanning direction (the direction orthogonal to the plane of FIG. 1). A wafer W is held on a Z tilt stage 58 mounted on the XY stage 14 by vacuum suction or the like via a wafer holder (not shown). The Z-tilt stage 58 adjusts the position of the wafer W in the Z direction (the position of the wafer) by, for example, three actuators (piezo elements or voice coil motors), and moves the XY plane (projection optical system PL). It has a function of adjusting the inclination angle of the wafer W with respect to the image plane of The position of the XY stage 14 is measured by an external laser interferometer 54 W through a movable mirror 52 W fixed on the Z tilt stage 58, and the measurement of the laser interferometer 54 W is performed. The value is supplied to the main controller 50.
ここで、 移動鏡は、 実際には、 X軸に垂直な反射面を有する X移動鏡と丫軸 に垂直な反射面を有する Y移動鏡とが存在し、 これに対応してレーザ干渉計も X軸位置計測用、 Y軸位置計測用、 及び回転 (ョーイング量、 ピッチング量、 ローリング量を含む) 計測用のものがそれぞれ設けられているが、 図 1では、 これらが代表的に、 移動鏡 5 2 W、 レーザ干渉計 5 4 Wとして示されている。 また、 Zチル卜ステージ 5 8上には、 ウェハ Wの近傍に、 ウェハ Wの露光面 と同じ高さの受光面を有し、 投影光学系 P Lを通過した露光光 I Lの光量を検 出するための照射量モニタ 5 9が設けられている。 照射量モニタ 5 9は、 露光 領域 4 2 Wよリー回り大きな X方向に延びる平面視長方形のハウジングを有し、 このハウジングの中央部に露光領域 4 2 Wとほぼ同じ形状のスリツ卜状の開口 が形成されている。 この開口は、 実際にはハウジングの天井面を形成する合成 石英等から成る受光ガラスの上面に形成された遮光膜の一部が取り除かれて形 成されている。 前記開口の真下にレンズを介して S i系 P I N型フ才卜ダイォ 一ド等の受光素子を有する光センサが配置されている。 Here, the moving mirror actually has an X moving mirror having a reflecting surface perpendicular to the X axis and a Y moving mirror having a reflecting surface perpendicular to the 丫 axis. X-axis position measurement, Y-axis position measurement, and rotation (including jogging, pitching, and rolling) measurements are provided, respectively. In Figure 1, these are typically used as moving mirrors. Shown as 52 W, laser interferometer 54 W. In addition, on the Z tilt stage 58, a light receiving surface having the same height as the exposure surface of the wafer W is provided near the wafer W, and the light amount of the exposure light IL passing through the projection optical system PL is detected. Dose monitor 59 is provided. The irradiation amount monitor 59 has a rectangular housing in a plan view extending in the X direction around the exposure area 42 W, which is larger than the exposure area 42 W. Is formed. This opening actually forms the ceiling surface of the housing It is formed by removing a part of the light shielding film formed on the upper surface of the light receiving glass made of quartz or the like. An optical sensor having a light receiving element such as a Si-type PIN-type photodiode is disposed directly below the opening via a lens.
照射量モニタ 5 9は、 露光領域 4 2 Wに照射される露光光 I しの強度測定に 用いられる。 照射量モニタ 5 9を構成する受光素子の受光量に応じた光量信号 が主制御装置 5 0に供給されるようになっている。  The irradiation amount monitor 59 is used for measuring the intensity of the exposure light I irradiated to the exposure area 42 W. A light amount signal corresponding to the amount of light received by the light receiving element constituting the irradiation amount monitor 59 is supplied to the main controller 50.
なお、 光センサは、 必ずしも Zチル卜ステージ 5 8の内部に設ける必要はな く、 Zチル卜ステージ 5 8の外部に光センサを配置し、 リレー光学系でリレー された照明光束を光ファイバ等を介してその光センサに導くようにしても良い ことは勿論である。  The optical sensor does not necessarily need to be provided inside the Z tilt stage 58, and an optical sensor is provided outside the Z tilt stage 58, and the illumination light beam relayed by the relay optical system is used for optical fiber or the like. Needless to say, the light sensor may be guided to the optical sensor via the optical sensor.
Zチル卜ステージ 5 8上には、 後述するレチクルァライメン卜等を行う際に 使用される基準マーク板 F Mが設けられている。 この基準マーク板 F Mは、 そ の表面がウェハ Wの表面とほぼ同一の高さとされている。 この基準マーク板 F Mの表面には、 レチクルァライメント用基準マーク、 ベースライン計測用基準 マーク等の基準マークが形成されている。  On the Z tilt stage 58, a reference mark plate FM used for performing a reticle alignment or the like described later is provided. The surface of the reference mark plate FM is substantially the same height as the surface of the wafer W. Reference marks such as a reticle alignment reference mark and a baseline measurement reference mark are formed on the surface of the reference mark plate FM.
また、 図 1では図面の錯綜を避ける観点から図示が省略されているが、 この 露光装置 1 0は、 実際にはレチクルァライメン卜を行うためのレチクルァライ メント系を備えている。  Although not shown in FIG. 1 from the viewpoint of avoiding complication of the drawings, the exposure apparatus 10 actually has a reticle alignment system for performing reticle alignment.
レチクル Rのァライメン卜を行う場合には、 まず主制御装置 5 0によりレチ クルステージ駆動部 4 9、 ウェハステージ駆動部 5 6を介してレチクルステー ジ R S T及び X Yステージ 1 4が駆動され、 矩形の露光領域 4 2 W内に基準マ ーク板 F M上のレチクルァライメン卜用基準マークが設定され、 その基準マー クにレチクル R上のレチクルマーク像がほぼ重なるようにレチクル Rと Zチル 卜ステージ 5 8との相対位置が設定される。 この状態で、 主制御装置 5 0によ リレチクルァライメン卜系を用いて両マークが撮像され、主制御装置 5 0では、 その撮像信号を処理して対応する基準マークに対するレチクルマークの投影像 の X方向、 Y方向の位置ずれ量を算出する。 When aligning the reticle R, first, the main controller 50 drives the reticle stage RST and the XY stage 14 via the reticle stage drive unit 49 and the wafer stage drive unit 56, thereby forming a rectangular shape. A reticle alignment reference mark on the reference mark plate FM is set in the exposure area 4 2 W, and the reticle R and Z tilt tilt so that the reticle mark image on the reticle R almost overlaps the reference mark The position relative to the stage 58 is set. In this state, both marks are imaged by the main controller 50 using a reticle alignment system, and the main controller 50 processes the image signals and projects the reticle marks onto the corresponding reference marks. image Calculate the amount of displacement in the X and Y directions.
また、 上記のレチクルのァライメン卜の結果得られた基準マークの投影像の 検出信号 (画像信号) に含まれるコントラス卜情報に基づいてフォーカスオフ セットゃレべリングオフセット (投影光学系 P Lの焦点位置、 像面傾斜など) を求めることも可能である。  In addition, based on the contrast information included in the detection signal (image signal) of the projected image of the reference mark obtained as a result of the alignment of the reticle, focus offset / leveling offset (focal position of the projection optical system PL) , Image plane tilt, etc.).
また、 本実施形態では、 上記のレチクルァライメン卜時に、 主制御装置 5 0 によって、 投影光学系 P Lの側面に設けられた不図示のウェハ側のオファクシ ス ·ァライメン卜センサのベースライン量の計測も行われる。 すなわち、 基準 マーク板 F Μ上には、 レチクルァライメン卜用基準マークに対して所定の位置 関係でベースライン計測用基準マークが形成されており、 レチクルァライメン 卜系を介してレチクルマークの位置ずれ量を計測する際に、 そのウェハ側のァ ライメン卜センサを介してベースライン計測用基準マークのそのァライメン卜 センサの検出中心に対する位置ずれ量を計測することで、 ァライメン卜センサ のベースライン量、 すなわちレチクル投影位置とァライメン卜センサとの相対 位置関係が計測される。  Also, in the present embodiment, at the time of the above reticle alignment, the main controller 50 controls the baseline amount of the wafer-side office-side alignment sensor (not shown) provided on the side surface of the projection optical system PL. Measurement is also performed. In other words, a reference mark for baseline measurement is formed on the reference mark plate F in a predetermined positional relationship with respect to the reference mark for reticle alignment, and the reticle mark is provided via the reticle alignment system. When measuring the amount of misalignment of the alignment sensor, the amount of misalignment of the baseline measurement reference mark with respect to the detection center of the alignment sensor is measured via the alignment sensor on the wafer side. The line amount, that is, the relative positional relationship between the reticle projection position and the alignment sensor is measured.
更に、 本実施形態の露光装置 1 0では、 図 1に示されるように、 主制御装置 5 0によってオン ·オフが制御される光源を有し、 投影光学系 P Lの結像面に 向けて多数のピンホールまたはスリツ卜の像を形成するための結像光束を、 光 軸 A Xに対して斜め方向より照射する照射光学系 6 0 aと、 それらの結像光束 のウェハ W表面での反射光束を受光する受光光学系 6 0 bとからなる斜入射光 式の多点焦点位置検出系 (フォーカスセンサ) が設けられている。 主制御装置 5 0では、 受光光学系 6 0 b内の図示しない平行平板の反射光束の光軸に対す る傾きを制御することにより、 投影光学系 P Lのフォーカス変動に応じて焦点 検出系 (6 0 a、 6 0 b ) にオフセットを与えてそのキャリブレーションを行 う。 これにより、 前述の露光領域 4 2 W内で投影光学系 P Lの像面とウェハ W の表面とがその焦点深度の範囲 (幅) 内で合致することになる。 なお、 本実施 形態と同様の多点焦点位置検出系 (フォーカスセンサ) の詳細な構成は、 例え ば特開平 6— 2 8 3 4 0 3号公報及びこれに対応する米国特許第 5, 4 4 8 , 3 3 2号等に開示されている。 本国際出願で指定した指定国又は選択した選択 国の国内法令が許す限りにおいて、 上記公報及び米国特許における開示を援用 して本明細書の記載の一部とする。 Further, as shown in FIG. 1, the exposure apparatus 10 of the present embodiment has a light source whose on / off is controlled by the main controller 50, and a large number of light sources are directed toward the image forming plane of the projection optical system PL. An irradiation optical system 60a for irradiating an imaging light beam for forming an image of a pinhole or a slit from an oblique direction with respect to the optical axis AX, and a reflection light beam of the imaging light beam on the surface of the wafer W An obliquely incident light type multi-point focal position detection system (focus sensor) composed of a light receiving optical system 60b for receiving light is provided. The main controller 50 controls the inclination of the reflected light flux of the parallel flat plate (not shown) in the light receiving optical system 60b with respect to the optical axis, so that the focus detection system (6 Calibration is performed by giving offsets to 0 a and 60 b). As a result, the image plane of the projection optical system PL and the surface of the wafer W coincide with each other within the range (width) of the depth of focus within the above-described exposure area 42 W. This implementation The detailed configuration of the multi-point focal position detection system (focus sensor) similar to the embodiment is described in, for example, Japanese Patent Application Laid-Open No. Hei 6-284403 and US Patent Nos. 5,448,333 corresponding thereto. No. 2, etc. To the extent permitted by the national laws of the designated or designated elected country in this international application, the disclosures in the above publications and U.S. patents are incorporated herein by reference.
走査露光時等に、 主制御装置 5 0では、 受光光学系 6 0 bからの焦点ずれ信 号(デフォーカス信号)、例えば Sカープ信号に基づいて焦点ずれが零となるよ うに Zチル卜ステージ 5 8の Z位置を不図示の駆動系を介して制御することに より、 ォー卜フォーカス(自動焦点合わせ)及びオートレべリングを実行する。 なお、 受光光学系 6 0 b内に平行平板を設けて焦点検出系(6 0 a , 6 0 b ) にオフセットを与えるようにしたのは、 例えば、 倍率補正のためにレンズエレ メン卜 7 0 aを上下することによりフォーカスも変化し、 また、 投影光学系 P Lが露光光 I Lを吸収することによリ結像特性が変化して結像面の位置が変動 するので、 かかる場合に焦点検出系にオフセットを与え、 焦点検出系の合焦位 置を投影光学系 P Lの結像面の位置に一致させる必要があるためである。 この ため、 本実施形態では、 レンズエレメント 7 0 aの上下量とフォーカス変化量 の関係も予め実験により求め、 例えばメモリ 5 1に記憶している。 なお、 レン ズエレメント 7 0 aの上下量とフォーカス変化量の関係は計算値を用いても良 い。 また、 才ートレべリングでは走査方向については行わず、 その走査方向と 直交する非走査方向のみに関して行うようにしても良い。  At the time of scanning exposure or the like, the main controller 50 sets the Z tilt stage so that the defocus becomes zero based on the defocus signal (defocus signal) from the light receiving optical system 60b, for example, the S-carp signal. The autofocus (automatic focusing) and the autoleveling are executed by controlling the Z position 8 through a drive system (not shown). The reason why a parallel flat plate is provided in the light receiving optical system 60b to give an offset to the focus detection system (60a, 60b) is that, for example, the lens element 70a is used for magnification correction. When the projection optical system PL absorbs the exposure light IL, the re-imaging characteristics change and the position of the imaging surface fluctuates. This is because it is necessary to apply an offset to the focal point and to make the focus position of the focus detection system coincide with the position of the imaging plane of the projection optical system PL. For this reason, in the present embodiment, the relationship between the vertical amount of the lens element 70a and the focus change amount is obtained in advance by experiments, and is stored in the memory 51, for example. The relationship between the vertical amount of the lens element 70a and the focus change amount may use a calculated value. In addition, the self-leveling may not be performed in the scanning direction, but may be performed only in the non-scanning direction orthogonal to the scanning direction.
前記主制御装置 5 0は、 C P U (中央演算処理装置)、 R O M (リード ·オン リ ·メモリ)、 R A M (ランダム ·アクセス■メモリ)等から成るいわゆるマイ クロコンピュー夕 (又はワークステーション) を含んで構成され、 これまでに 説明した各種の制御を行う他、 露光動作が的確に行われるように、 例えばレチ クル Rとウェハ Wの同期走査、 ウェハ Wのステッピング、 露光タイミング等を 制御する。 また、 本実施形態では、 主制御装置 5 0は、 後述するように走査露 光の際の露光量の制御を行ったり、 投影光学系 P Lの結像特性の変動量を演算 にて算出し、 その算出結果に基づいて結像特性補正コントローラ 7 8を介して 投影光学系 P Lの結像特性を調整する等の他、 装置全体を統括制御する。 具体的には、 主制御装置 5 0は、 例えば走査露光時には、 レチクル Rがレチ クルステージ R S Tを介して +丫方向 (又は一 Y方向) に速度 VR= Vで走査さ れるのに同期して、 X Yステージ 1 4を介してウェハ Wが露光領域 4 2 Wに対 してー丫方向 (又は +丫方向) に速度 Vw= )8 ■ V ( はレチクル Rからウェハ Wに対する投影倍率) で走査されるように、 レーザ干渉計 5 4 R、 5 4 Wの計 測値に基づいてレチクルステージ駆動部 4 9、 ウェハステージ駆動部 5 6をそ れぞれ介してレチクルステージ R S T、 Χ Υステージ 1 4の位置及び速度をそ れぞれ制御する。 また、 ステッピングの際には、 主制御装置 5 0ではレーザ干 渉計 5 4 Wの計測値に基づいてウェハステージ駆動部 5 6を介して Χ Υステー ジ 1 4の位置を制御する。 The main controller 50 includes a so-called microcomputer (or workstation) including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. In addition to performing the various controls described above, it controls, for example, synchronous scanning of the reticle R and the wafer W, stepping of the wafer W, exposure timing, and the like so that the exposure operation is properly performed. Further, in the present embodiment, the main control device 50 controls the scanning exposure as described later. It controls the amount of exposure in the case of light, calculates the amount of change in the imaging characteristics of the projection optical system PL by calculation, and, based on the calculation result, passes the projection optical system PL through the imaging characteristic correction controller 78. In addition to adjusting the imaging characteristics of the device, it controls the entire system. Specifically, for example, during scanning exposure, main controller 50 synchronizes with reticle R being scanned at speed V R = V in the + 丫 direction (or one Y direction) via reticle stage RST. Te, the wafer W is against the exposure area 4 2 W via the XY stage 1 4 over丫direction (or +丫direction) = the velocity V w) 8 ■ V (projection magnification with respect to the wafer W from the reticle R is) Reticle stage RST, レ し て through reticle stage drive unit 49 and wafer stage drive unit 56 based on the measured values of laser interferometers 54 R and 54 W, respectively. The position and speed of the stage 14 are controlled respectively. At the time of stepping, main controller 50 controls the position of stage 14 via wafer stage drive unit 56 based on the measured value of laser interferometer 54W.
次に、 本実施形態の露光装置 1 0において所定枚数 (Ν枚) のウェハ W上に レチクルパターンの露光を行う場合の露光シーケンスについて主制御装置 5 0 の制御動作を中心として説明する。  Next, an exposure sequence when a reticle pattern is exposed on a predetermined number (Ν) of wafers W in the exposure apparatus 10 of the present embodiment will be described focusing on the control operation of the main controller 50.
まず、 前提条件について説明する。  First, the preconditions will be described.
① オペレータによりコンソール等の入出力装置 6 2 (図 1参照) から入力さ れたショッ卜配列、 ショッ卜サイズ、 各ショッ卜の露光順序その他の必要なデ 一夕に基づいて、 予めショットマップデータ (各ショット領域の露光順序と走 査方向とを定めたデータ) が作成され、 メモリ 5 1 (図 1参照) 内に格納され ているものとする。  ① Shot map data is prepared in advance based on the shot arrangement, shot size, exposure order of each shot, and other necessary data input from the input / output device 62 (see Fig. 1) by the operator. (Data defining the exposure order and scanning direction of each shot area) are created and stored in the memory 51 (see FIG. 1).
② また、 インテグレー夕センサ 4 6の出力は、 Ζチル卜ステージ 5 8上で像 面 (即ち、 ウェハの表面) と同じ高さに設置された不図示の基準照度計の出力 に対して予め較正 (キャリブレーション) されているものとする。 インテグレ 一夕センサ 4 6の較正とは、 インテグレー夕センサ 4 6の出力を、 像面上の露 光量に変換するための変換係数 (或いは変換関数) を得ることである。 この変 換係数を用いると、 インテグレー夕センサ 4 6の出力より間接的に像面上に与 えられている露光量 (エネルギ) を計測できることになる。 ② In addition, the output of the integrator sensor 46 is pre-calibrated against the output of a reference illuminometer (not shown) installed on the tilt stage 58 at the same height as the image plane (ie, the surface of the wafer). (Calibration). Calibration of the Integra sensor 46 means that the output of the Integra sensor 46 is Obtaining a conversion coefficient (or conversion function) for converting to light quantity. When this conversion coefficient is used, the amount of exposure (energy) given to the image plane can be indirectly measured from the output of the integrator sensor 46.
③ また、 上記キャリブレーションが完了したインテグレー夕センサ 4 6の出 力に対して、 ビームモニタ機構 1 6 4内のエネルギモニタ、 光増幅部 1 6 1内 の光電変換素子 1 . 8 0、 1 8 1及び波長変換部 1 6 3内の光電変換素子 1 8 2 等の出力もキャリブレーションされ、 インテグレータセンサ 4 6の出力に対す る各センサ出力の相関係数も予め求められ、 メモリ 5 1内に格納されている。 ③ In addition, in response to the output of the integrator sensor 46 after the above calibration is completed, the energy monitor in the beam monitor mechanism 164 and the photoelectric conversion elements 1.80, 18 in the optical amplifier 161 1 and the outputs of the photoelectric conversion elements 18 2 in the wavelength converter 16 3 are also calibrated, and the correlation coefficient of each sensor output with respect to the output of the integrator sensor 46 is also obtained in advance. Is stored.
④ さらに、 上記キャリブレーションが完了したインテグレー夕センサ 4 6の 出力に対して反射光モニタ 4 7の出力がキャリブレーションされ、 インテグレ 一夕センサ 4 6の出力と反射光モニタ 4 7の出力との相関係数が予め求められ てメモリ 5 1内に格納されているものとする。 ④ Furthermore, the output of the reflected light monitor 47 is calibrated against the output of the integrator sensor 46 after the above calibration is completed, and the output of the integrator sensor 46 and the output of the reflected light monitor 47 are compared. It is assumed that the number of relations is obtained in advance and stored in the memory 51.
まず、 オペレータによりコンソール等の入出力装置 6 2 (図 1参照) から照 明条件 (投影光学系の開口数 N . Α ·、 2次光源の形状(開口絞り 2 4の種類)、 コヒ一レンスファクタびゃレチクルパターンの種類 (コンタクトホール、 ライ ンアンドスペース等)、 レチクルの種類(位相差レチクル、ハーフ I ^一ンレチク ル等)、及び最小線幅又は露光量許容誤差など)を含む露光条件が入力され、 こ の入力に応じて、 主制御装置 5 0が、 投影光学系 P Lの不図示の開口絞りの設 定、 照明系開口絞り板 2 4の開口の選択設定、 レジス卜感度に応じた目標積算 露光量 (設定光量に対応する量である) の設定等を行う。 このとき、 同時に主 制御装置 5 0では、 目標積算露光量を得るための光源装置 1 6からの出力光量 を設定光量にほぼ一致させるための、バンドル一ファイバ 1 7 3の出力をオン、 及びオフにすべきチャネルの選択を行い、 この選択指令を光量制御装置 1 6 C に与える。 これにより、 後述する走査露光の際にレーザ光源 1 6 O Aの発光と ほぼ同時に、 光量制御装置 1 6 Cにより、 前述した第 1の機能により選択指令 に応じて各チャネルのファイバ増幅器 1 7 1 nのオン ·オフが実行され、露光量 の粗調整が実行されることとなる。 First, the lighting conditions (numerical aperture N. の of the projection optical system, the shape of the secondary light source (type of aperture stop 24), the coherence Exposure conditions, including factors and reticle pattern types (contact holes, line and space, etc.), reticle types (phase difference reticle, half I-one reticle, etc.) and minimum line width or exposure tolerance, etc. In response to this input, the main controller 50 sets the aperture stop (not shown) of the projection optical system PL, selects and sets the aperture of the illumination system aperture stop plate 24, and responds to the registry sensitivity. Set the target integrated exposure amount (the amount corresponding to the set light amount). At this time, at the same time, the main controller 50 turns on and off the output of the bundle-one fiber 173 to make the output light amount from the light source device 16 for obtaining the target integrated exposure amount substantially coincide with the set light amount. Is selected, and this selection command is given to the light quantity control device 16C. Thus, almost at the same time as the emission of the laser light source 16 OA during the scanning exposure to be described later, the light quantity control device 16 C causes the fiber amplifiers 17 1 1 n of each channel to respond to the selection command by the first function described above. Is turned on and off, and the exposure Will be roughly adjusted.
次に、 主制御装置 5 0では、 不図示のレチクルローダを用いて露光対象のレ チクル Rをレチクルステージ R S T上にロードする。  Next, main controller 50 loads reticle R to be exposed onto reticle stage R ST using a reticle loader (not shown).
次いで、 前述した如く、 レチクルァライメン卜系を用いてレチクルァライメ ン卜を行うとともに、 ベースライン計測を行う。  Next, as described above, reticle alignment is performed using the reticle alignment system, and baseline measurement is performed.
次に、 主制御装置 5 0では、 不図示のウェハ搬送系にウェハ Wの交換を指示 する。 これにより、 ウェハ搬送系及び X Yステージ 1 4上の不図示のウェハ受 け渡し機構によってウェハ交換 (ステージ上にウェハが無い場合は、 単なるゥ ェハロード) が行われ、 次いで特開平 9— 1 8 6 0 6 1号公報及び特開平 9一 3 6 2 0 2号公報並びにこれらに対応する米国特許出願番号 0 8 Z 6 7 8 7 8 8号等に開示されるいわゆるサーチァライメン卜及びファインァライメン卜 (例えば、特開昭 6 1 - 4 4 4 2 9号公報及びこれに対応する米国特許第第 4, 7 8 0, 6 1 7号等に開示される最小 2乗法を利用した統計学的手法を用いて ウェハ W上の全てのショッ卜領域の配列座標を求めるェンハンス卜 ·グローバ ル -ァライメン卜 (E G A ) 等) の一連のァライメン卜工程の処理を行う。 こ れらのウェハ交換、 ウェハァライメン卜は、公知の露光装置と同様に行われる。 本国際出願で指定した指定国又は選択した選択国の国内法令が許す限りにおい て、 上記各公報並びにこれらに対応する米国特許出願及び米国特許における開 示を援用して本明細書の記載の一部とする。  Next, main controller 50 instructs a wafer transfer system (not shown) to replace wafer W. As a result, the wafer is exchanged (if there is no wafer on the stage, a simple wafer load) is performed by a wafer transfer system and a wafer transfer mechanism (not shown) on the XY stage 14. The so-called search element and finer disclosed in Japanese Patent Application No. 061 and Japanese Patent Application Laid-Open No. Hei 9-136202 and U.S. Pat. (For example, statistics using the least squares method disclosed in Japanese Patent Application Laid-Open No. 61-44492 and corresponding US Pat. Nos. 4,780,617). A series of alignment processes, such as Enhancement, Global-Alignment (EGA), etc., that determine the array coordinates of all shot areas on the wafer W using a biological method. These wafer exchange and wafer alignment are performed in the same manner as in a known exposure apparatus. To the extent permitted by the national laws of the designated or designated elected country in this international application, the disclosures in the above publications and corresponding U.S. patent applications and U.S. patents shall be incorporated by reference. Department.
次に、 上記のァライメン卜結果及びショットマップデータに基づいて、 ゥェ ハ W上の各ショッ卜領域の露光のための走査開始位置にウェハ Wを移動させる 動作と、 前述した走査露光動作とを繰り返し行って、 ステップ ·アンド,スキ ヤン方式でウェハ W上の複数のショッ卜領域にレチクルパターンを転写する。 この走査露光中に、 主制御装置 5 0では、 露光条件及びレジス卜感度に応じて 決定された目標積算露光量をウェハ Wに与えるため、 インテグレー夕センサ 4 6の出力をモニタしつつ光量制御装置 1 6 Cに指令を与える。 これにより、 光 量制御装置 1 6 Cでは、 前述した第 1の機能により露光量の粗調整を行うとと もに、 前述した第 2の機能、 第 3の機能により、 光源装置 1 6からのレーザビ ー厶 (紫外パルス光) の周波数及びピークパワーを制御し、 露光量の微調整を 実行する。 Next, based on the alignment result and the shot map data, an operation of moving the wafer W to a scanning start position for exposure of each shot area on the wafer W and the above-described scanning exposure operation are described. The reticle pattern is repeatedly transferred to a plurality of shot areas on the wafer W by a step-and-scan method. During this scanning exposure, the main controller 50 applies the target integrated exposure amount determined according to the exposure conditions and the resist sensitivity to the wafer W, so that the output of the integrator sensor 46 is monitored while the light amount controller 50 is monitored. Give a command to 16 C. This allows light In the amount control device 16C, the coarse adjustment of the exposure amount is performed by the first function described above, and the laser beam (light beam) from the light source device 16 is controlled by the second and third functions described above. It controls the frequency and peak power of ultraviolet pulse light, and performs fine adjustment of the exposure.
また、 主制御装置 5 0では、 照明系開口絞り板 2 4を駆動装置 4 0を介して 制御し、 更にステージ系の動作情報に同期して可動レチクルプラインド 3 0 B の開閉動作を制御する。  Further, the main controller 50 controls the illumination system aperture stop plate 24 via the driving device 40, and further controls the opening / closing operation of the movable reticle blind 30B in synchronization with the operation information of the stage system. .
1枚目のウェハ Wに対する露光が終了すると、 主制御装置 5 0では、 不図示 のウェハ搬送系にウェハ Wの交換を指示する。 これにより、 ウェハ搬送系及び X Yステージ 1 4上の不図示のウェハ受け渡し機構によってウェハ交換が行わ れ、 以後上記と同様にしてその交換後のウェハに対してサーチァライメン卜、 ファインァライメン卜を行う。 また、 この場合、 主制御装置 5 0により 1枚目 のウェハ Wに対する露光開始からの投影光学系 P Lの結像特性 (フォーカスの 変動を含む) の照射変動が、 インテグレータセンサ 4 6及び反射光モニタ 4 7 の計測値に基づいて求められ、 この照射変動を補正するような指令値を結像特 性補正コントローラ 7 8に与えるとともに受光光学系 6 0 bにオフセッ卜を与 える。 また、 主制御装置 5 0では、 大気圧センサ 7 7の計測値に基づいて、 投 影光学系 P Lの結像特性の大気圧変動分も求めて、 この照射変動を補正するよ うな指令値を結像特性補正コントローラ 7 8に与えるとともに受光光学系 6 0 bにオフセットを与える。  When the exposure for the first wafer W is completed, main controller 50 instructs a wafer transfer system (not shown) to replace wafer W. As a result, the wafer is exchanged by the wafer transfer system and the wafer transfer mechanism (not shown) on the XY stage 14, and thereafter, the search alignment and the fine alignment are performed on the replaced wafer in the same manner as described above. Perform In this case, the main controller 50 causes the irradiation fluctuation of the imaging characteristics (including the focus fluctuation) of the projection optical system PL from the start of the exposure of the first wafer W to the integrator sensor 46 and the reflected light monitor. A command value, which is obtained based on the measurement value of 47 and corrects this irradiation variation, is given to the imaging characteristic correction controller 78 and an offset is given to the light receiving optical system 60b. The main controller 50 also obtains the atmospheric pressure fluctuation of the imaging characteristics of the projection optical system PL based on the measurement value of the atmospheric pressure sensor 77, and issues a command value for correcting this irradiation fluctuation. The offset is given to the imaging characteristic correction controller 78 and the light receiving optical system 60b.
そして、 上記と同様に、 このウェハ W上の複数のショット領域にステップ, アンド ·スキャン方式でレチクルパターンを転写する。 そして、 この 2枚目の ウェハの露光が終了すると、以後、上記と同様にして、 ウェハ交換、ステップ- アンド ·スキャン方式の露光が順次繰り返し行われる。  Then, similarly to the above, the reticle pattern is transferred to a plurality of shot areas on the wafer W by a step-and-scan method. When the exposure of the second wafer is completed, the wafer exchange and the step-and-scan exposure are sequentially repeated in the same manner as described above.
ところで、 上記の N枚のウェハ Wに対する露光を行う際に、 主制御装置 5 0 では、 ビームモニタ機構 1 6 4のモニタ結果に基づいてレーザ制御装置 1 6 B を介してレーザ光源 1 6 O Aの発振波長を設定波長に安定的に維持するような フィードバック制御を行っている。 このため、 波長変動による投影光学系 P L の収差 (結像特性) の発生、 又はその変動が防止され、 パターン転写中にその 像特性 (像質などの光学的特性) が変化することがない。 By the way, when performing the exposure on the N wafers W, the main controller 50 controls the laser controller 16 B based on the monitoring result of the beam monitor mechanism 16 4. Feedback control is performed to maintain the oscillation wavelength of the laser light source 16 OA stably at the set wavelength via the. For this reason, generation of aberration (imaging characteristics) of the projection optical system PL due to wavelength fluctuation or its fluctuation is prevented, and the image characteristics (optical characteristics such as image quality) do not change during pattern transfer.
この一方、 主制御装置 5 0では、 結像特性補正コントローラ 4 4に指示を与 えて駆動素子 7 4 a, 7 4 b , 7 4 cを駆動して投影光学系 P Lの上記の大気 圧変動分を含む環境変動分を補正する代わりに、 1枚目のウェハ Wの露光が開 始されてから所定のタイミング毎に、 環境センサ 7 7の計測値に基づいて標準 状態からの気圧、 温度、 遨度等の変化を求め、 その気圧、 温度、 湿度等の変化 に起因する投影光学系 P Lの結像特性の環境変動分をほぼ相殺するための波長 変更量を計算で求め、 該波長変更量に応じてレーザ光源 1 6 O Aの発振波長を 積極的に変更することとしても良い。 なお、 環境センサ 7 7は、 大気圧を検出 するセンサであっても良い。  On the other hand, the main controller 50 gives instructions to the imaging characteristic correction controller 44 to drive the drive elements 74a, 74b, and 74c, and the above-described atmospheric pressure fluctuation component of the projection optical system PL. Instead of compensating for environmental fluctuations including the following, at predetermined timings after exposure of the first wafer W is started, the atmospheric pressure, temperature, and scale from the standard state are determined based on the measurement values of the environmental sensors 77. Degrees of change, etc. are calculated, and the amount of wavelength change for almost canceling the environmental change of the imaging characteristics of the projection optical system PL due to the change of the atmospheric pressure, temperature, humidity, etc. is calculated, and the amount of change in wavelength is calculated. The oscillation wavelength of the laser light source 16 OA may be positively changed accordingly. The environment sensor 77 may be a sensor that detects atmospheric pressure.
かかる発振波長の変更は、 主制御装置 5 0から指示に基づき、 レーザ制御装 置 1 6 Bがビームモニタ機構 1 6 4を構成するエタロン素子の温度を積極的に 制御して、 エタロン素子の透過率が最大となる共鳴波長 (検出基準波長) がー 致している設定波長 (目標波長) を変更すると共に、 この変更後の設定波長に D F B半導体レーザ 1 6 0 Aの発振波長が一致するように、 D F B半導体レー ザ 1 6 O Aの温度をフィードバック制御することにより容易に達成される。 これにより、 露光装置 1 0の稼働中に、 大気圧、 温度、 湿度などの変化に起 因して生じる投影光学系 P Lの収差、 投影倍率、 及び焦点位置などの結像特性 の変動を同時に相殺することができる。 すなわち、 この D F B半導体レーザ 1 6 O Aの発振波長の変更にょリ、 あたかも標準状態からの環境の変動がなかつ たかのような状態 (即ち、 光学性能の変動量が相殺された状態) にすることが できる。  Such a change of the oscillation wavelength is performed based on an instruction from the main controller 50, in which the laser controller 16B actively controls the temperature of the etalon element constituting the beam monitor mechanism 164 to transmit the etalon element. Change the set wavelength (target wavelength) at which the resonance wavelength (detection reference wavelength) at which the efficiency becomes the maximum is adjusted, and make sure that the oscillation wavelength of the DFB semiconductor laser 160 A matches the changed set wavelength. This is easily achieved by feedback controlling the temperature of the DFB semiconductor laser 16 OA. As a result, while the exposure apparatus 10 is operating, fluctuations in the imaging characteristics such as aberrations, projection magnifications, and focal positions of the projection optical system PL caused by changes in atmospheric pressure, temperature, humidity, and the like are simultaneously canceled. can do. That is, in response to the change of the oscillation wavelength of the DFB semiconductor laser 16 OA, it is possible to make a state as if the environment did not fluctuate from the standard state (ie, a state in which the fluctuations in the optical performance were offset). .
このような波長変更、 より具体的には、 設定波長の変更、 及びこの変更後の 設定波長を基準とするレーザ光源 1 6 O Aの発振波長の安定化制御は次のよう な場合に行われる。 Such a wavelength change, more specifically, a change in the set wavelength, and the change after this change The control of stabilizing the oscillation wavelength of the laser light source 16 OA based on the set wavelength is performed in the following cases.
例えば大気圧を採り上げて説明すると、 通常、 標準大気圧は、 露光装置が設 置される納入先 (工場など) の平均大気圧に設定されることが多い。 従って、 露光装置を製造する組立地と、 露光装置が設置される納入先 (移設地) とに標 高差があるときは、 例えば標準大気圧 (平均大気圧など) 下に投影光学系など が設置されているかのように、 組立地ではその標高差に対応する波長だけ露光 波長をシフ卜させた上で投影光学系などの調整を行い、 移設地ではその波長を 露光波長に戻す、 あるいは組立地では露光波長のもとで投影光学系などの調整 を行い、 移設地でその標高差を相殺するように露光波長をシフ卜させる。 他の 環境条件、 すなわち温度、湿度等についても同様のことが言える。 これにより、 組み立て地と納入先との標高差や気圧差、 更には環境 (クリーンルーム内の雰 囲気) の違いなどに応じて生じる投影光学系 P Lの結像特性 (収差など) の変 動を相殺でき、 納入先で露光装置の立ち上げに要する時間を短縮することが可 能になる。 さらに、 露光装 の稼働中に、 大気圧変化などに起因して生じる投 影光学系 P Lの収差、 投影倍率、 及び焦点位置などの変動も相殺でき、 常に最 良の結像状態でパターン像を基板上に転写することが可能となる。  For example, taking atmospheric pressure as an example, the standard atmospheric pressure is usually set to the average atmospheric pressure of the delivery destination (eg, factory) where the exposure apparatus is installed. Therefore, when there is an elevation difference between the assembly site where the exposure apparatus is manufactured and the destination where the exposure apparatus is installed (relocation place), for example, the projection optical system and the like are operated under standard atmospheric pressure (such as average atmospheric pressure). As if installed, the exposure wavelength was shifted by the wavelength corresponding to the elevation difference at the assembly site, and then the projection optical system was adjusted.At the relocation site, the wavelength was returned to the exposure wavelength, or assembly was performed. On the ground, the adjustment of the projection optical system is performed under the exposure wavelength, and the exposure wavelength is shifted at the relocation site so as to offset the elevation difference. The same can be said for other environmental conditions, such as temperature and humidity. This offsets fluctuations in the imaging characteristics (such as aberrations) of the projection optical system PL caused by differences in elevation and pressure between the assembly site and the delivery destination, as well as differences in the environment (atmosphere in the clean room). It is possible to shorten the time required for starting up the exposure apparatus at the delivery destination. Furthermore, during operation of the exposure device, fluctuations in the projection optical system PL caused by changes in atmospheric pressure, etc., such as aberration, projection magnification, and focal position, can be offset, and the pattern image can always be obtained in the best imaging state. Transfer onto a substrate becomes possible.
このように、 本実施形態では、 例えば投影光学系によって照明光の波長を変 更することと、 その投影光学系の設置環境 (周囲の気体の圧力、 温度、 湿度な ど) を変更することは実質的に等価であることを利用している。 このとき、 投 影光学系の屈折素子の硝材の種類が単一であるときには、 その等価性が完全に 成立し、 硝材が複数種類であってもその等価性はほぼ成立する。 従って、 設置 環境に対する投影光学系 (特に屈折素子) の屈折率の変化特性を用いて、 照明 光の波長のみを変化させることによって、 実質的に投影光学系の設置環境が変 化した場合と等価な状態を実現することができる。  As described above, in the present embodiment, for example, changing the wavelength of the illumination light by the projection optical system and changing the installation environment (pressure, temperature, humidity, etc. of the surrounding gas) of the projection optical system are not possible. The fact that they are substantially equivalent is used. At this time, when the type of the glass material of the refraction element of the projection optical system is single, the equivalence is completely established, and even when there are a plurality of types of glass materials, the equivalence is almost satisfied. Therefore, by changing only the wavelength of the illumination light using the change characteristic of the refractive index of the projection optical system (particularly the refractive element) with respect to the installation environment, it is substantially equivalent to the case where the installation environment of the projection optical system changes. Can be realized.
なお、 標準大気圧は任意で良いが、 例えば投影光学系などの光学性能が最良 となるようにその調整を行うときの基準となる大気圧であることが望ましく、 この場合には、標準大気圧では投影光学系などの光学性能の変動量が零となる。 また、投影光学系 P Lが空気以外の雰囲気中に設置される場合、大気圧とは、 投影光学系 P Lの周囲の雰囲気 (気体) の圧力となる。 すなわち、 本明細書に おいて、 大気圧とは通常の意味、 すなわち大気 (空気) の圧力より広く、 雰囲 気気体の圧力を含む。 The standard atmospheric pressure may be set arbitrarily, but for example, the optical performance of the projection optical system is the best. It is desirable that the atmospheric pressure be a reference when the adjustment is made so that the variation in the optical performance of the projection optical system or the like becomes zero at the standard atmospheric pressure. When the projection optical system PL is installed in an atmosphere other than air, the atmospheric pressure is the pressure of the atmosphere (gas) around the projection optical system PL. That is, in this specification, the atmospheric pressure has a normal meaning, that is, wider than the pressure of the atmosphere (air) and includes the pressure of the atmospheric gas.
なお、 主制御装置 5 0では、 上記の波長の変更によりキャンセルできない投 影光学系 P Lの結像特性の環境変動分がある場合には、 主制御装置 5 0では、 前記設定波長の変更の度毎に、 結像特性補正コントローラ 7 8を介して駆動素 子 7 4 a、 7 4 b , 7 4 cを駆動して設定波長の変更により補正される投影光 学系 P Lの環境変動分を除く、 結像特性変動を補正する。 これにより、 投影光 学系 P Lの結像特性の環境変動分の大部分が上記の設定波長の変更によリ補正 され、 投影光学系 P Lの残りの環境変動分、 照射変動分等が、 結像特性補正コ ントローラ 7 8による駆動素子 7 4 a、 7 4 b、 7 4 cの駆動により補正され る。 この結果、 投影光学系 P Lの結像特性をほぼ完全に補正した状態で高精度 な露光が行われる。  In the main controller 50, if there is an environmental change in the imaging characteristic of the projection optical system PL that cannot be canceled due to the above-mentioned wavelength change, the main controller 50 sets the degree of change of the set wavelength. In each case, the driving elements 74a, 74b, and 74c are driven via the imaging characteristic correction controller 78 to exclude environmental fluctuations in the projection optical system PL that are corrected by changing the set wavelength. Correct the imaging characteristic fluctuation. As a result, most of the environmental fluctuations in the imaging characteristics of the projection optical system PL are re-corrected by changing the set wavelength, and the remaining environmental fluctuations and irradiation fluctuations of the projection optical system PL are formed. The correction is performed by driving the drive elements 74 a, 74 b, and 74 c by the image characteristic correction controller 78. As a result, high-precision exposure is performed with the imaging characteristics of the projection optical system PL almost completely corrected.
更に、 主制御装置 5 0は、 前記設定波長の変更間では、 環境変動を考慮して 結像特性変動を補正することとしても良い。 設定波長の変更は上述した所定の タイミングで行われるが、 この設定波長の変更間隔が長いと、 その間で気圧、 温度、 湿度等の変動が生じるが、 このような場合にもそれらに起因する投影光 学系の結像特性の変動分を補正することができる。  Further, the main controller 50 may correct the imaging characteristic fluctuation in consideration of the environmental fluctuation during the change of the set wavelength. The change of the set wavelength is performed at the above-mentioned predetermined timing, but if the change interval of the set wavelength is long, fluctuations in the atmospheric pressure, temperature, humidity, etc. occur during that time. Variations in the imaging characteristics of the optical system can be corrected.
ここで、 前記所定のタイミングは、 所定枚数のウェハ Wの露光終了毎のタイ ミングであっても良く、 ウェハ W上の 1ショッ卜の露光終了の度毎のタイミン グであっても良い。 ここで、 所定枚数は 1枚であっても良く、 1 ロットに相当 する枚数であっても良い。  Here, the predetermined timing may be timing each time exposure of a predetermined number of wafers W is completed, or timing each time exposure of one shot on the wafer W is completed. Here, the predetermined number may be one, or may be a number corresponding to one lot.
あるいは、 前記所定のタイミングは、 露光条件の変更の度毎のタイミングで あっても良い。 また、 露光条件の変更とは、 照明条件の変更の他、 レチクルの 交換等の広い意味での露光に関する条件が変更された場合の全てを含む。 例え ば、 いわゆる二重露光時のレチクル交換や照明系開口絞りの変更と並行して波 長の変更を行えば、 時間ロスが殆どないので、 スループットの低下を防止する ことができる。 Alternatively, the predetermined timing is a timing every time the exposure condition is changed. There may be. Further, the change of the exposure condition includes not only the change of the illumination condition but also all the cases where the condition regarding the exposure in a broad sense such as a change of a reticle is changed. For example, if the wavelength is changed in parallel with the change of the reticle and the change of the aperture stop of the illumination system during the so-called double exposure, there is almost no time loss, so that a decrease in throughput can be prevented.
あるいは、 所定のタイミングは、 環境センサ 7 7の計測値に基づいて得られ る大気圧等の物理量の変化が所定量以上変化したタイミングであっても良く、 あるいは投影光学系 P Lの光学性能を演算する間隔 (例えば数; s ) に合わせ て、 ほぼリアルタイムで行っても良い。 あるいは所定のタイミングは、 予め定 められた所定時間毎のタイミングであっても良い。  Alternatively, the predetermined timing may be a timing at which a change in a physical quantity such as atmospheric pressure obtained based on the measurement value of the environment sensor 77 changes by a predetermined amount or more, or calculates the optical performance of the projection optical system PL. It may be performed almost in real time according to the interval (for example, number; s). Alternatively, the predetermined timing may be a timing at a predetermined time interval.
更に、 照射変動分の補正をも含めてレーザ光の波長変更によリ対処すること も可能である。 このとき、 複数の代表的な波長毎に実験又はシミュレーション にて照射変動モデルを求めておくとよい。 ここで、 変更された波長が、 照射変 動モデルを求めた波長の間である場合は、 例えば補間計算などによって結像特 性又はその変動量を算出することが望ましい。  Further, it is possible to cope with the problem by changing the wavelength of the laser beam, including the correction of the irradiation variation. At this time, an irradiation variation model may be obtained by experiment or simulation for each of a plurality of representative wavelengths. Here, when the changed wavelength is between the wavelengths for which the irradiation variation model is obtained, it is desirable to calculate the imaging characteristic or the amount of variation thereof by, for example, interpolation calculation.
また、 波長シフトによってウェハ W上に塗布されるレジス卜 (感光剤) の感 度特性が変化することがあり、 この場合、 主制御装置 5 0では、 その感度特性 の変化に応じて後述する積算露光のパラメータ、 すなわち走査速度、 照明領域 の幅、 照明光の強度、 及び発振周波数の少なくとも 1つを変更することにより 露光量を制御することが望ましい。 なお、 複数の代表的な波長に対応して実験 又はシミュレーションにてレジス卜の感度特性を求めておくと良く、 さらに変 更された波長が、 感度特性を求めた波長の間であるときは、 例えば補間計算な どによつてその感度特性を算出することが望ましい。  In addition, the sensitivity characteristic of the resist (photosensitive agent) applied on the wafer W may change due to the wavelength shift. In this case, the main controller 50 performs the integration described later according to the change in the sensitivity characteristic. It is desirable to control the exposure amount by changing at least one of the exposure parameters, that is, the scanning speed, the width of the illumination area, the intensity of the illumination light, and the oscillation frequency. It is preferable to determine the sensitivity characteristics of the resist by experiments or simulations corresponding to a plurality of representative wavelengths, and when the changed wavelength is between the wavelengths for which the sensitivity characteristics were determined, For example, it is desirable to calculate the sensitivity characteristic by interpolation calculation or the like.
なお、 前述した露光量 (光量) の粗調整を、 実露光前にテスト発光を行い、 露光量設定値に対し、 1 %以下の精度で制御を確実に行うようにしても良い。 本実施形態の露光量の粗調整のダイナミックレンジは、 1〜1 / 1 2 8の範 囲内で設定可能であるが、 通常要求されるダイナミックレンジは、 典型的には 1〜1 Z 7程度であるため、光出力をオンにすべきチャネル数(光ファイバ数) を 1 2 8〜 8の間で制御することによって行えば良い。 このように、 本実施 形態では、 各チャネルの光出力の個別オン ·オフによる露光量制御により、 ゥ ェハ毎のレジスト感度等の違いにあわせた露光量の粗調整を正確に行うことが できる。 The above-described coarse adjustment of the exposure amount (light amount) may be performed by performing test emission before actual exposure, and performing control with an accuracy of 1% or less with respect to the exposure amount set value. The dynamic range of the coarse adjustment of the exposure amount according to the present embodiment is in the range of 1 to 1/128. Although it can be set within the range, the required dynamic range is typically about 1 to 1 Z7, so the number of channels (the number of optical fibers) for which the optical output should be turned on is 128 to 8 What is necessary is to perform by controlling between. As described above, in the present embodiment, the coarse adjustment of the exposure amount according to the difference in the resist sensitivity or the like for each wafer can be accurately performed by controlling the exposure amount by individually turning on / off the light output of each channel. .
従って、 本実施形態では、 従来のエキシマレーザ露光装置に用いられていた N Dフィルタ等のエネルギ粗調器が不要となる。  Therefore, in this embodiment, an energy coarse adjuster such as an ND filter used in a conventional excimer laser exposure apparatus is not required.
また、 上述した光量制御装置 1 6 Cによる、 第 2、 第 3の機能による光量制 御は、 制御速度が速く、 制御精度が高いという特徴を持っため、 以下の現状の 露光装置に要求されている制御要請を確実に満たすことが可能である。  In addition, the light amount control by the second and third functions by the above-described light amount control device 16C has characteristics that the control speed is fast and the control accuracy is high. It is possible to surely satisfy the required control requirements.
すなわち、 同一ウェハ内における、 例えばレジス卜の膜厚のばらつきに起因 して生じる、 ショット領域 (チップ毎) のプロセスばらつきを補正する露光量 制御のための要請である、 ダイナミックレンジが設定露光量の ± 1 0 %程度、 ショッ卜間ステッピング時阛である 1 0 0 m s程度の時間内に設定値に制御す ること、 制御精度として設定露光量の ± 1 %程度、 1ショット領域の線幅均一 性を実現するための露光制御のための要請である、 制御精度として典型的には 1ショットの露光時間である 2 O m s e cの時間内に設定露光量の ± 0 . 2 % に設定すること、 制御速度 1 m s程度、 の全てを満たす。  In other words, the dynamic range is a requirement for exposure control to correct the process variation in the shot area (for each chip) caused by, for example, the variation in the thickness of the resist in the same wafer. Approximately ± 10%, control to the set value within about 100 ms, which is the time of stepping between shots, Control accuracy is approximately ± 1% of the set exposure amount, and line width of one shot area is uniform Is a requirement for exposure control to realize the characteristic, the control accuracy is typically set to ± 0.2% of the set exposure within the time of 2 O msec which is the exposure time of one shot, Control speed is about 1 ms.
従って、 露光量制御のためには、 光量制御装置 1 6 Cでは、 第 2、 第 3の機 能による光量制御の少なくとも一方を行えば足りる。  Therefore, in order to control the exposure amount, the light amount control device 16C only needs to perform at least one of the light amount control by the second and third functions.
また、 本実施形態の露光装置 1 0のようなレーザ光源 (パルス光源) を有す る走査型露光装置では、 ウェハ Wの走査速度 (スキャン速度) を Vw、 ウェハ W 上のスリット状の露光領域 4 2 Wの走査方向の幅 (スリット幅) を D、 レーザ 光源のパルスの繰り返し周波数を「とすると、 パルス発光間にウェハ Wが移動 する間隔は V WZ Fであるため、ウェハ上の 1点当たりに照射すべき露光光 I L のパルス数 (露光パルス数) Nは次式 (3 ) で表される。 In a scanning exposure apparatus having a laser light source (pulse light source) such as the exposure apparatus 10 of the present embodiment, the scanning speed (scan speed) of the wafer W is set to V w , and the slit-shaped exposure on the wafer W is performed. Region 4 If the width in the scanning direction (slit width) of 2 W is D and the repetition frequency of the pulse of the laser light source is “, the interval at which the wafer W moves between pulse emission is V W ZF. Exposure light IL to be irradiated per spot The number of pulses (the number of exposure pulses) N is expressed by the following equation (3).
N = D Z ( Vw/ F ) …… ( 3 ) N = DZ (V w / F) …… (3)
パルスエネルギを Pとすると、 単位時間にウェハ上の 1点当たりに与えられ るべきエネルギは、 次式 (4 ) で表される。  Assuming that the pulse energy is P, the energy to be given per point on the wafer per unit time is expressed by the following equation (4).
E = N P = P D/ ( Vw/ F ) …… ( 4 ) E = NP = PD / (V w / F) …… (4)
従って、 走査型露光装置では、 スリット幅 D、 スキャン速度 Vw、 レーザ光源 のパルスの繰り返し周波数 F、 パルスエネルギ Pのいずれかを制御することに より、 露光量 (積算露光量) の制御が可能である。 応答速度の問題から走査露 光中にスリット幅 Dを調整することには難点があるので、 スキャン速度 Vw、 レ 一ザ光源のパルスの繰リ返し周波数 F、 パルスエネルギ Pのいずれかを制御す れば良い。 Therefore, in a scanning exposure apparatus, the exposure amount (integrated exposure amount) can be controlled by controlling any of the slit width D, the scanning speed Vw , the pulse repetition frequency F of the laser light source, and the pulse energy P. It is. There is a difficulty in adjusting the slit width D during scanning exposure due to the problem of response speed, so control either the scanning speed V w , the pulse repetition frequency F of the laser light source, or the pulse energy P Just do it.
従って、本実施形態の露光装置 1 0においても、光量制御装置 1 6 Cの第 2、 第 3の機能による光量制御のいずれかと、 スキャン速度とを組み合わせて、 露 光量を制御するようにしても、 勿論良い。  Therefore, also in the exposure apparatus 10 of the present embodiment, the exposure light quantity may be controlled by combining any one of the light quantity control by the second and third functions of the light quantity control apparatus 16C and the scan speed. Well, of course.
例えば、 ウェハ W上に転写すべきレチクルパターンに応じてウェハ Wの露光 条件を変更する、 例えば照明光学系の瞳面上での照明光の強度分布 (即ち 2次 光源の形状や大きさ) を変化させたり、 あるいは投影光学系 P Lのほぼ瞳面上 でその光軸を中心とする円形領域を遮光する光学フィルタを挿脱する。 この露 光条件の変更によってウェハ W上での照度が変化するが、 このことはレチクル パターンの変更によっても生じる。 これは、 パターンの遮光部 (又は透過部) の占有面積の違いによるものである。 そこで、 露光条件及びレチクルパターン の少なくとも一方の変更によって照度が変化するときは、 ウェハ (レジス卜) に適正な露光量が与えられるように、 前述した周波数とピークパワーとの少な くとも一方を制御することが望ましい。 このとき、 周波数及びピークパワーの 少なくとも一方に加えてレチクル及びウェハの走査速度を調整するようにして も良い。 これまでの説明から明らかなように、 本実施形態では、 主制御装置 5 0によ つて、 第〗の制御装置、 第 2の制御装置、 第 3の制御装置のすべてが実現され ているが、 これらの制御装置を別々の制御装置によって構成しても良いことは 勿論である。 For example, the exposure condition of the wafer W is changed according to the reticle pattern to be transferred onto the wafer W. For example, the intensity distribution of the illumination light on the pupil plane of the illumination optical system (ie, the shape and size of the secondary light source) is Change or insert or remove an optical filter that shields a circular area centered on the optical axis almost on the pupil plane of the projection optical system PL. The change in the exposure condition changes the illuminance on the wafer W, which also occurs due to the change in the reticle pattern. This is due to the difference in the area occupied by the light-shielding part (or transmission part) of the pattern. Therefore, when the illuminance changes due to a change in at least one of the exposure condition and the reticle pattern, at least one of the above-described frequency and peak power is controlled so that an appropriate exposure amount is given to the wafer (register). It is desirable to do. At this time, in addition to at least one of the frequency and the peak power, the scanning speed of the reticle and the wafer may be adjusted. As is clear from the above description, in the present embodiment, all of the second control device, the second control device, and the third control device are realized by the main control device 50. Of course, these control devices may be constituted by separate control devices.
以上説明した本実施形態の光量制御装置 1 6 Cは、 前述の如く、 光経路から の光出力の個別オン ·オフによる光量制御機能 (第 1の機能) と、 E O M 1 6 0 Cから出力されるパルス光の周波数制御による光量制御機能 (第 2の機能) と、 E O M 1 6 0 Cから出力されるパルス光のピークパワー制御による光量制 御機能 (第 3の機能) とを有しているので、 第 1の機能と、 第 2の機能及び第 3の機能の少なくとも一方とにより、光経路 1 7 2 nの光出力の個別オン ·オフ による段階的な光量制御に加えて、 各段階間の光量の微調整が E O M 1 6 0 C から出力されるパルス光の周波数及びピークパワーの少なくとも一方の制御に より可能になるので、 結果的に光量の連続制御が可能となり、 所定範囲内であ れば設定光量が如何なる値に設定されても、 出力光の光量をその設定光量に一 致させることが可能になっている。 As described above, the light amount control device 16C of the present embodiment described above has a light amount control function (first function) by individually turning on and off the light output from the light path, and the light output from the EOM 16C. It has a light quantity control function (second function) by frequency control of pulsed light and a light quantity control function (third function) by peak power control of pulse light output from EOM160C. since, the first function, by at least one of the second function and a third function, in addition to the stepwise light amount control by the individual on-off of the light output of the optical path 1 7 2 n, between each stage Fine adjustment of the light intensity of light is possible by controlling at least one of the frequency and peak power of the pulsed light output from the EOM 1600C. Output light, no matter what value the set light intensity is set to. The amount can be made to match the set amount of light.
また、 光量制御装置 1 6 Cでは、 第 2の機能と第 3の機能とにより、 E O M 1 6 0 Cから出力されるパルス光の周波数制御に加えてピークパワーを更に制 御することができるので、 パルス光のピークパワーに変動があるような場合で あっても、 精度の良い光量制御が可能となる。  In addition, in the light quantity control device 16C, the second function and the third function allow the peak power to be further controlled in addition to the frequency control of the pulse light output from the EOM 160C. Even if the peak power of the pulse light fluctuates, accurate light quantity control can be performed.
しかしながら、 本発明がこれに限定されるものではなく、 本発明に係る光源 装置を構成する光量制御装置は、 上記第 1〜第 3の機能の少なくとも一つのみ を有していても良い。  However, the present invention is not limited to this, and the light amount control device constituting the light source device according to the present invention may have at least one of the first to third functions.
本実施形態に係る露光装置 1 0によると、 主制御装置 5 0では、 露光に先立 つて、 前述した絶対波長キャリブレーション、 及びそれに続く設定波長キヤリ プレーシヨンを行い、 露光中は、 その設定波長キャリブレーションが終了した ビームモニタ機構のモニタ結果に基づいてレーザ制御装置 1 6 Bを介してレー ザ光源 1 6 O Aの温度及び電流をフィードバック制御する。 すなわち、 主制御 装置 5 0では、 設定波長キャリブレーションが終了したビームモニタ機構 1 6 4のモニタ結果に基づいてレーザ光の中心波長を所定の設定波長に確実に維持 するような波長安定化制御を行いつつ、 レーザ光をレチクル Rに照射して該レ チクル Rのパターンを投影光学系 P Lを介してウェハ Wに転写するので、 雰囲 気の温度変動等の影響の少ない高精度な露光が可能になる。 According to the exposure apparatus 10 according to this embodiment, the main controller 50 performs the above-described absolute wavelength calibration and subsequent set wavelength calibration prior to exposure, and sets the set wavelength during the exposure. The calibration is completed via the laser controller 16B based on the monitoring result of the beam monitor mechanism. Feedback control of the temperature and current of the light source 16 OA. In other words, the main controller 50 performs wavelength stabilization control for surely maintaining the center wavelength of the laser beam at the predetermined set wavelength based on the monitoring result of the beam monitor mechanism 164 after the set wavelength calibration is completed. While irradiating the reticle R with a laser beam and transferring the pattern of the reticle R to the wafer W via the projection optical system PL, high-precision exposure that is less affected by temperature fluctuations in the atmosphere is possible. become.
また、 露光装置 1 0によると、 主制御装置 5 0が、 ウェハ Wの露光が開始さ れてから前述した所定のタイミング毎に、 環境センサ 7 7の計測値に基づいて 標準状態からの環境 (気圧、 温度、 湿度等) の変化に起因する投影光学系 P L の結像特性の変動分をほぼ相殺するための波長変更量を計算で求め、 該波長変 更量に応じて設定波長を変更する。 この結果、 投影光学系 P Lの諸収差が同時 に補正され、 主制御装置 5 0では、 その変更後の設定波長を基準としてビーム モニタ機構 1 6 4を用いてレーザ光の中心波長を所定の設定波長に確実に維持 するような波長安定化制御を行いつつ、レーザ光をレチクル Rに照射して露光、 すなわち、 レチクルパターンの投影光学系 P Lを介したウェハ W上への転写を 行う。 この場合、 結果的に環境の変動が存在しなかったかのような状態 (すな わち、 光学性能の変動が相殺された状態) で、 精度良く露光が行われることと なる。  Further, according to the exposure apparatus 10, the main controller 50 sets the environment (standard state) from the standard state based on the measurement value of the environment sensor 77 at each of the above-mentioned predetermined timings after the exposure of the wafer W is started. Calculation of a wavelength change amount for almost canceling out a change in the imaging characteristics of the projection optical system PL due to a change in the atmospheric pressure, temperature, humidity, and the like, and changing the set wavelength according to the wavelength change amount. . As a result, various aberrations of the projection optical system PL are corrected at the same time, and the main controller 50 sets the center wavelength of the laser beam to a predetermined value by using the beam monitor mechanism 164 based on the set wavelength after the change. The reticle R is irradiated with a laser beam and exposed, that is, the reticle pattern is transferred onto the wafer W via the projection optical system PL while performing wavelength stabilization control so as to reliably maintain the wavelength. In this case, as a result, exposure can be performed with high accuracy in a state where there is no change in the environment (ie, a state in which the change in optical performance has been offset).
また、 本実施形態の露光装置 1 0では、 主制御装置 5 0が、 前記設定波長の 変更の度毎に、 結像特性補正コントローラ 7 8を介して駆動素子 7 4 a、 7 4 b、 7 4 cを駆動して設定波長の変更により補正される投影光学系 P Lの環境 変動分を除く、 結像特性変動を補正する。 これにより、 投影光学系 P Lの結像 特性の環境変動分の大部分が上記の設定波長の変更により補正され、 投影光学 系 P Lの残りの環境変動分、 照射変動分、 温度変動分等が、 結像特性補正コン 卜ローラ 7 8による駆動素子 7 4 a、 7 4 b、 7 4 cの駆動により補正される。 この結果、 投影光学系 P Lの結像特性をほぼ完全に補正した状態で高精度な露 光が行われる。 Also, in the exposure apparatus 10 of the present embodiment, the main controller 50 changes the drive elements 74 a, 74 b, and 7 via the imaging characteristic correction controller 78 every time the set wavelength is changed. 4 Drive c to correct the imaging characteristic fluctuation except for the environmental fluctuation of the projection optical system PL that is corrected by changing the set wavelength. As a result, most of the environmental fluctuations in the imaging characteristics of the projection optical system PL are corrected by changing the set wavelength, and the remaining environmental fluctuations, irradiation fluctuations, temperature fluctuations, and the like of the projection optical system PL are corrected. The correction is made by driving the driving elements 74a, 74b, and 74c by the imaging characteristic correction controller 78. As a result, a highly accurate exposure can be achieved with the imaging characteristics of the projection optical system PL almost completely corrected Light is done.
なお、 上記実施形態では、 レーザ光源 1 6 O Aの発振波長の制御のため、 レ 一ザ光源 1 6 0 Aの直後でそのレーザ光をビームモニタ機構 1 6 4によリモニ タするものとしたが、 これに限らず、 例えば図 5中に点線で示されるように、 波長変換部 1 6 3内 (あるいは波長変換部 1 6 3の後方) で光束を分岐して、 これをビームモニタ機構 1 6 4と同様のビームモニタ機構 1 8 3でモニタする ようにしても良い。 そして、 このビームモニタ機構 1 8 3によるモニタ結果に 基づいて、 波長変換が正確に行われているか否かを検出し、 この検出結果に基 づいて主制御装置 5 0がレーザ制御装置 1 6 Bをフィードバック制御するよう にしても良い。 勿論、 両方のビームモニタ機構のモニタ結果を用いてレーザ光 源 1 6 O Aの発振波長制御を行っても良い。 さらに、 前述した投影光学系 P L の環境 (例えば大気圧を少なくとも含む) 変動分を補正するための設定波長の 変更の際に、 ビームモニタ機構 1 8 3を構成するエタロン素子の検出基準波長 をその設定波長に変更することとしても良い。  In the above embodiment, the laser light is monitored by the beam monitor mechanism 164 immediately after the laser light source 160 A in order to control the oscillation wavelength of the laser light source 16 OA. However, the present invention is not limited to this. For example, as shown by a dotted line in FIG. 5, a light beam is branched in the wavelength conversion section 163 (or behind the wavelength conversion section 163) and is split into a beam monitor mechanism 16 The beam may be monitored by the same beam monitor mechanism 18 as in 4. Then, based on the result of monitoring by the beam monitor mechanism 183, it is detected whether or not the wavelength conversion is performed accurately. Based on the result of the detection, the main controller 50 controls the laser controller 16B May be feedback controlled. Of course, the oscillation wavelength control of the laser light source 16OA may be performed using the monitoring results of both beam monitoring mechanisms. Further, when changing the set wavelength for compensating for the above-mentioned fluctuations in the environment of the projection optical system PL (for example, including at least atmospheric pressure), the detection reference wavelength of the etalon element constituting the beam monitor mechanism 183 is changed. The wavelength may be changed to the set wavelength.
なお、 上記実施形態中で説明した波長検出装置の共鳴波長温度依存性の代わ りに、 波長検出装置を構成するフアブリペロー ·エタロンの共振器長をピエゾ 素子などで可変にし、共鳴波長の共振器長依存性を使用するようにしても良い。 これにより高速で波長を変更することが可能となる。  Instead of the temperature dependence of the resonance wavelength of the wavelength detector described in the above embodiment, the resonator length of the Fabry-Perot etalon constituting the wavelength detector is made variable by a piezo element or the like, and the resonator length of the resonance wavelength is changed. Dependencies may be used. This makes it possible to change the wavelength at high speed.
なお、 上記実施形態では、 各光経路 (各チャネル) からの光出力をオン -ォ フする際に、 ファイバ増幅器の励起光の強度を切り換えることにより行う場合 について説明したが、 本発明がこれに限定されるものではなく、 例えば、 各光 経路に対する入射光を遮光する機械的又は電気的なシャッタ、 あるいは各光経 路からの光の出射を阻止する機械的又は電気的なシャツ夕を設ける等種々考え られる。  In the above embodiment, the case where the optical output from each optical path (each channel) is turned on and off by switching the intensity of the pump light of the fiber amplifier has been described. Without limitation, for example, a mechanical or electrical shutter that blocks light incident on each optical path, or a mechanical or electrical shirt that blocks light emission from each optical path is provided. There are various possibilities.
また、 上記実施形態では、 光増幅部 1 6 1が 1 2 8チャネルの光経路を有す る場合について説明したが、 光増幅部は 1チャネルであっても良く、 かかる場 合であっても、 前述した E O M等の光変調器から出力されるパルス光の周波数 制御、 ピークパワー制御による光量、 露光量の制御は好適に適用できる。 Further, in the above embodiment, the case where the optical amplifying section 161 has an optical path of 128 channels has been described. However, the optical amplifying section may have one channel, Even in this case, the control of the light amount and the exposure amount by the frequency control and the peak power control of the pulse light output from the optical modulator such as the EOM described above can be suitably applied.
なお、 上記実施形態では、 偏光調整装置 1 6 Dが光ファイバ増幅器 1 7 1 n の射出光を円偏光に調整しているが、 偏光調整が互いに同様な楕円偏光化にと どまる場合には、 四分の一波長板 1 6 2に替えて、 偏波面を回転する二分の一 波長板と、 該二分の一波長板と光学的に直列接続された四分の一波長板との組 合わせを使用することにより、 光ファイバ増幅器 1 7 1 nから射出された複数 の光束を同一の偏光方向の直線偏光に変換することができる。 ここで、 二分の 一波長板と四分の一波長板との直列接続において、 どちらを上流側に配置して もよい。 In the above embodiment, although the polarization adjustment device 1 6 D is adjusted light emitted optical fiber amplifier 1 7 1 n into circularly polarized light, when the the polarization adjustment mutually similar elliptically polarized reduction Domaru is A combination of a half-wave plate rotating the plane of polarization, and a quarter-wave plate optically connected in series with the half-wave plate, instead of the quarter-wave plate 16 2 By using, a plurality of light beams emitted from the optical fiber amplifier 17 1 n can be converted into linearly polarized light having the same polarization direction. Here, in the series connection of the half-wave plate and the quarter-wave plate, either of them may be arranged on the upstream side.
また、 上記実施形態では、 四分の一波長板 1 6 2に入射する光は、 光フアイ バ増幅器 1 7 1 nの射出光としたが、 複数の光導波用の光ファイバから射出さ れた複数の光束を四分の一波長板 1 6 2に入射させることにしてもよい。 In the above-described embodiment, the light incident on the quarter-wave plate 16 2 is the light emitted from the optical fiber amplifier 17 1 n , but is emitted from a plurality of optical waveguide optical fibers. A plurality of light beams may be incident on the quarter-wave plate 16 2.
また、上記実施形態では、光増幅部 1 6 1が 1 2 8チャネルの光経路を有し、 これらの光経路の出射端部を構成する 1 2 8本の光ファイバによってバンドル —ファイバが構成される場合について説明したが、 光経路の本数、 従ってバン ドルーフアイバを形成するフアイバの本数は任意でよく、 本発明に係る光源装 置が適用される製品、例えば露光装置で要求される仕様(ウェハ上での照度)、 及び光学性能、 すなわち照明光学系や投影光学系の透過率、 波長変換部の変換 効率、 及び各光経路の出力などに応じてその本数を決定すればよい。 かかる場 合であっても、 前述した光変調器から出力されるパルス光の周波数制御、 ピー クパワー制御による光量、 露光量の制御は好適に適用できる。  In the above embodiment, the optical amplification section 16 1 has 128 channels of optical paths, and a bundle—fiber is constituted by 128 optical fibers constituting the emission ends of these optical paths. However, the number of optical paths, and thus the number of fibers forming the band roof eyer, may be arbitrarily determined, and a product to which the light source device according to the present invention is applied, for example, a specification required for an exposure apparatus (on a wafer) Illuminance), and the optical performance, that is, the transmittance of the illumination optical system and the projection optical system, the conversion efficiency of the wavelength conversion unit, the output of each optical path, and the like, may be determined. Even in such a case, the control of the light amount and the exposure amount by the frequency control and the peak power control of the pulse light output from the optical modulator can be suitably applied.
さらに、 上記実施形態では、 紫外光の波長を、 A r Fエキシマレーザ又は F 2 レーザの波長とほぼ同一に設定するものとしたが、その設定波長は任意で良く、 この設定すべき波長に応じて、 レーザ光源 1 6 O Aの発振波長や波長変換部 1 6 3の構成及び高調波の倍率などを決定すれば良い。 なお、 設定波長は、 一例 として、 ウェハ上に転写すべきパターンのデザインルール(線幅、 ピッチなど) に応じて決定するようにしても良く、 更にはその決定に際して前述の露光条件 ゃレチクルの種類 (位相シフ卜型か否か) などを考慮しても良い。 Furthermore, in the above embodiment, the wavelength of the ultraviolet light, it is assumed to be set to almost the same as A r F excimer laser or F 2 laser wavelength, the predetermined wavelength may be arbitrary, depending on the wavelength to be the setting Then, the oscillation wavelength of the laser light source 16 OA, the configuration of the wavelength conversion unit 16 3, the harmonic magnification, and the like may be determined. The setting wavelength is an example. Alternatively, the pattern may be determined according to the design rule (line width, pitch, etc.) of the pattern to be transferred onto the wafer. In addition, the above-described exposure conditions, reticle type (phase shift type or not) May be considered.
なお、上記実施形態では、光ファイバ増幅器 1 7 1 nそれぞれから射出される 光束の偏光状態を円偏光 (又は楕円偏光) に揃えるための偏光調整装置 1 6 D を設けるとともに、 これらの光束の全てを 1枚の四分の一波長板 1 6 2によつ て同一方向の直線偏光に変換して射出する場合について説明したが、 例えば、 光増幅部の構成を変更等すれば、 偏光調整装置や四分の一波長板は必ずしも設 けなくとも良い。 In the above embodiment, the polarization adjusting device 16 D for aligning the polarization state of the light beam emitted from each of the optical fiber amplifiers 17 1 n with circularly polarized light (or elliptically polarized light) is provided. Has been described by using a single quarter-wave plate 162 to emit linearly polarized light in the same direction. It is not always necessary to provide a quarter-wave plate.
《変形例》  《Modification》
図 7には、 このように偏光調整装置や四分の一波長板 (偏光方向変換装置) を不要とすることができる、 光増幅部 1 6 1の構成の一例が示されている。 以 下においては、 重複説明を避けるため、 前述した実施形態と同一若しくは同等 の構成部分については同一符号を用いるとともに、 その説明を省略し若しくは 簡略化するものとする。  FIG. 7 shows an example of the configuration of the optical amplifying section 161 which can eliminate the need for the polarization adjusting device and the quarter-wave plate (polarization direction changing device). In the following, in order to avoid redundant description, the same reference numerals are used for the same or equivalent components as those in the above-described embodiment, and the description thereof will be omitted or simplified.
この図 7に示される光増幅部 1 6 1は、 前述した E O M 1 6 0 Cからのパル ス光を増幅するもので、 E O M 1 6 0 Cからのパルス光を時間順に周期的に振 リ分けて分岐 (例えば、 1 2 8分岐) する分岐及び遅延部 1 6 7と、 複数の光 増幅器としてのファイバ増幅器 1 9 0とを含んで構成されている。  The optical amplifier 161, shown in Fig. 7, amplifies the pulse light from the EOM 160C described above, and periodically distributes the pulse light from the EOM 160C in chronological order. It is configured to include a branching / delaying section 167 that branches (for example, 128 branches) and a fiber amplifier 190 as a plurality of optical amplifiers.
ファイバ増幅器 1 9 0は、 直線敷設された光導波路部材としての増幅用ファ ィバ 1 7 5、 ポンプ光を発生する励起用半導体レーザ 1 7 8、 上述の E O M 1 6 0 Cの出力光とポンプ光とを合成し、 こうして得られた合成光を増幅用ファ ィバ 1 7 5に供給する W D M l 7 9を備えている。 そして、 増幅用ファイバ 1 7 5及び W D M 1 7 9は容器 1 9 1に収容されている。  The fiber amplifier 190 is composed of an amplification fiber 175 as an optical waveguide member laid in a straight line, a pumping semiconductor laser 178 for generating pump light, and the above-described output light of the EOM 160 C and a pump. A WDM 179 is provided for combining the light with the light and supplying the combined light obtained to the fiber 175 for amplification. Then, the amplification fiber 175 and the WDM 179 are housed in a container 191.
前記増幅用ファイバ 1 7 5は、 フォスフェイ卜ガラスを主材とし、 コアとク ラッドを有し、 コアに E r、 あるいは E rと Y bとの 2種のイオンが高密度に ドープされた光ファイバが用いられている。 かかるフォスフェイ卜ガラス光フ アイバには、 従来のシリカガラス光ファイバよりも高密度で E r等の希土類元 素をドープすることができ、 同一の光増幅率を得るために必要なファイバ長が 従来のシリカガラス光ファイバの 1 / 1 0 0程度となる。 たとえば、 従来は数 m〜数 1 0 mの長さとなっていたものが、 数 c m〜数 1 0 c m程度の長さで足 りる。 このため、 増幅用ファイバ 1 7 5では直線状敷設が可能となっており、 この図 7の変形例においても不図示の基材表面 (平面) に形成された直線状の V溝に増幅用ファイバ 1 7 5を敷設することにより、直線状敷設を行っている。 なお、増幅用ファイバ 1 7 5には、 2重クラッド構造を持つダブル'クラッド · ファイバの構造を採用するが可能である。 The amplification fiber 175 is mainly composed of phosphate glass, has a core and a clad, and has two cores of Er, or Er and Yb, in a high density. A doped optical fiber is used. Such a phosphate glass optical fiber can be doped with a rare earth element such as Er at a higher density than a conventional silica glass optical fiber, and the fiber length required to obtain the same optical amplification factor is conventionally increased. About 1/100 of the silica glass optical fiber. For example, what used to be several meters to several ten meters in the past, a few centimeters to several ten centimeters is sufficient. For this reason, it is possible to lay a straight line in the amplification fiber 1 75, and in the modified example of FIG. 7 as well, the amplification fiber By laying 1 7 5, a straight line is laid. Note that a double-clad fiber structure having a double clad structure can be adopted as the amplification fiber 175.
以上のように構成されたファイバ増幅器 1 9 0において、 増幅用ファイバ 1 7 5に、 励起用半導体レーザ 1 7 8が発生したポンプ光が W D M 1 7 9を介し て供給された状態で、 W D M 1 7 9を介してパルス光が入射し増幅用ファイバ 1 7 5のコア中を進行すると、 誘導放射が発生し、 パルス光が増幅される。 か かる光増幅にあたって、 増幅用ファイバ 1 7 5は従来のものより非常に短く、 かつ、 高い増幅率を有するので、 入射時のパルス光の偏光状態をほぼ維持しつ つ、 高輝度のパルス光が出力される。 また、 増幅用ファイバ 1 7 5の長さが非 常に短いため、 誘導ラマン散乱や自己位相変調によるスぺクトルの広がりも小 さなものとなっている。  In the fiber amplifier 190 configured as described above, the pump light generated by the pumping semiconductor laser 178 is supplied to the amplification fiber 175 via the WDM 179 and the WDM 1 When the pulsed light enters via 79 and travels through the core of the amplification fiber 175, stimulated radiation is generated, and the pulsed light is amplified. In such optical amplification, since the amplification fiber 175 is much shorter than the conventional one and has a high amplification factor, high-intensity pulse light is maintained while almost maintaining the polarization state of the pulse light at the time of incidence. Is output. In addition, since the length of the amplification fiber 175 is very short, the spread of the spectrum due to stimulated Raman scattering and self-phase modulation is also small.
すなわち、 フォスフェイ卜ガラスを用いて、 従来のシリカガラスに比べて 1 0 0倍高密度の E rをドープする場合、 従来のシリカガラスよりも、 誘導ラマ ン散乱が起こる閾値を決める要因の 1つであるラマン利得係数 (Raman Gain 係数) が 2倍程度となっているが、 この分を考慮してもシリカガラスの場合よ りも 5 0倍程度の強度の光を出力することができる。 また、 単位長さ当たりの 増幅率を〗 0 0倍程度にできるので、 同一の増幅率を得るのに必要なファイバ 長を 1 0 0分の 1程度にすることができる。 さらに、 誘導ラマン散乱のしきい 値はファイバ長に反比例すると試算できるので、 ファイバ長を 1 0 0分の 1 に することで、 ラマン散乱の影響を受けずに 1 0 0倍程度の強度の光を出力でき る。 In other words, when doping Er with a density of 100 times higher than that of conventional silica glass using phosphate glass, one of the factors that determine the threshold value at which stimulated Raman scattering occurs compared to conventional silica glass. The Raman gain coefficient is about twice that of this, but even with this factor in mind, it is possible to output light that is about 50 times stronger than silica glass. Further, since the gain per unit length can be made about 100 times, the fiber length necessary to obtain the same gain can be made about 1/100. Furthermore, the threshold of stimulated Raman scattering Since the value can be estimated to be inversely proportional to the fiber length, by reducing the fiber length by a factor of 100, light with an intensity of about 100 times can be output without being affected by Raman scattering.
また、 自己位相変調によるスペクトルの広がりは増幅用ファイバ 1 7 5の長 さにほぼ比例するが、 増幅用ファイバ 1 7 5の長さは従来のものよりも非常に 短いので、 自己位相変調によるスぺクトルの広がりも従来と比べて十分に小さ く抑制することができる。  The spread of the spectrum due to self-phase modulation is almost proportional to the length of the amplifying fiber 175, but the length of the amplifying fiber 175 is much shorter than that of the conventional one, so the spread due to the self-phase modulation is small. The spread of the vector can be suppressed sufficiently smaller than before.
従って、 この変形例のファイバ増幅器 1 9 0では、従来よりも高強度であり、 かつ、 スペクトルの広がりも小さな増幅光を得ることができる。 このため、 効 率良く狭帯域の光を得ることができる。  Therefore, in the fiber amplifier 190 of this modified example, amplified light having higher intensity and a smaller spectrum spread than before can be obtained. Therefore, narrow-band light can be obtained efficiently.
また、 増幅用光ファイバ 1 7 5が直線状に敷設されており、 かつ、 ほぼ密閉 構造の容器 1 9 1に収容され、 増幅用光ファイバ 1 7 5の周囲環境がほぼ一定 に維持されているので、 入射時の偏光状態をほぼ維持した出力光が得られる。 前記励起用半導体レーザ 1 7 8は、 D F B半導体レーザ 1 6 O Aにおける発 振波長よりも短い波長(例えば、 9 8 0 n m)の光をポンプ光として発生する。 このポンプ光が W D M 1 7 9を介して増幅用ファイバ 1 7 5に供給され、 それ により E rが励起され、 いわゆるエネルギ準位の反転分布が発生する。 なお、 前述と同様、 励起用半導体レーザ 1 7 8は、 光量制御装置 1 6 Cによって制御 される。  In addition, the amplification optical fiber 175 is laid in a straight line and is housed in a substantially sealed container 191, so that the environment around the amplification optical fiber 175 is maintained substantially constant. Therefore, output light can be obtained in which the polarization state at the time of incidence is almost maintained. The pumping semiconductor laser 178 generates light having a wavelength (for example, 980 nm) shorter than the oscillation wavelength of the DFB semiconductor laser 16OA as pump light. This pump light is supplied to the amplification fiber 175 via the WDM 179, thereby exciting Er and generating a so-called inverted population of energy levels. As described above, the excitation semiconductor laser 178 is controlled by the light amount control device 16C.
また、 この変形例では、 各ファイバ増幅器 1 9 0のゲインの差を抑制するた め、 ファイバ増幅器 1 9 0で出力の一部が分岐され、 それぞれの分岐端に設け られた光電変換素子 1 8 1によってそれぞれ光電変換されるようになっている。 これらの光電変換素子 1 8 1の出力信号が光量制御装置 1 6 Cに供給されるよ うになつている。  Also, in this modification, in order to suppress the difference in gain between the fiber amplifiers 190, a part of the output is branched by the fiber amplifier 190, and the photoelectric conversion elements 18 provided at the respective branch ends are provided. 1 is adapted to be photoelectrically converted. Output signals of these photoelectric conversion elements 18 1 are supplied to a light quantity control device 16 C.
光量制御装置 1 6 Cでは、 各ファイバ増幅器 1 9 0からの光出力が一定にな るように(即ちバランスするように)、各励起用半導体レーザ 1 7 8のドライブ 電流をフィードバック制御するようになっている。 In the light amount control device 16C, the drive of each pumping semiconductor laser 178 is performed so that the optical output from each fiber amplifier 190 is constant (that is, balanced). The current is feedback-controlled.
また、 光量制御装置 1 6 Cでは、 光電変換素子 1 8 2の出力信号に基づいて 波長変換器 1 6 3における光強度をモニタし、 波長変換部 1 6 3からの光出力 が所定の光出力となるように、 励起用半導体レーザ 1 7 8のドライブ電流をフ イードバック制御している。  Also, the light amount control device 16C monitors the light intensity of the wavelength converter 163 based on the output signal of the photoelectric conversion element 182, and the light output from the wavelength conversion unit 163 is a predetermined light output. The drive current of the semiconductor laser for excitation 178 is feedback-controlled so that
このような構成とすることにより、 各ファイバ増幅器 1 9 0の増幅率が一定 化されるため、 各ファイバ増幅器 1 9 0間に偏った負荷がかかることがなく全 体として均一な光強度が得られる。 また、 波長変換部 1 6 3における光強度を モニタすることにより、 予定される所定の光強度をフィードバックし、 所望の 紫外光出力を安定して得ることができる。  By adopting such a configuration, the amplification factor of each fiber amplifier 190 is kept constant, so that there is no uneven load between the fiber amplifiers 190 and uniform light intensity can be obtained as a whole. Can be In addition, by monitoring the light intensity in the wavelength converter 163, a predetermined predetermined light intensity can be fed back to stably obtain a desired ultraviolet light output.
図 7の光増幅部は、 前述した図 3の光増幅部に代えてそのまま採用すること ができ、 このような図 7の光増幅部 1 6 1を採用した光源装置によれば、 長さ の短い増幅用ファイバ 1 7 5によって高い増幅率で入射光を増幅することがで きる。 このため、 増幅用ファイバ 1 7 5を経由することによって発生する偏光 状態の変化を低減しつつ、 高強度の光を波長変換部 1 6 3に供給することがで きる。 また、 増幅にあたって光が経由する経路の長さが短くなるので、 誘導ラ マン散乱や自己位相変調によるスぺクトルの広がりも抑制することができる。 したがって、 簡易な構成で狭帯域の波長変換光を効率良く発生することができ る。  The optical amplifier of FIG. 7 can be used as it is in place of the optical amplifier of FIG. 3 described above. According to such a light source device employing the optical amplifier 161 of FIG. The short amplification fiber 175 can amplify the incident light at a high amplification rate. For this reason, it is possible to supply high-intensity light to the wavelength conversion section 163 while reducing the change in the polarization state caused by passing through the amplification fiber 175. In addition, since the length of the path through which light passes during amplification becomes shorter, the spread of the spectrum due to stimulated Raman scattering and self-phase modulation can be suppressed. Therefore, it is possible to efficiently generate narrow-band wavelength converted light with a simple configuration.
また、 増幅用ファイバ 1 7 5を直線状に敷設しているので、 偏光状態の変化 の原因となる径方向の応力の非対称性の発生を防止することができるので、 入 射時の偏光状態をほぼ維持した出力光を得ることができる。  In addition, since the amplification fiber 175 is laid in a straight line, it is possible to prevent the occurrence of radial stress asymmetry which may cause a change in the polarization state. Almost maintained output light can be obtained.
また、 増幅用ファイバ 1 7 5をほぼ密閉構造を有する容器 1 9 1に収容して いるので、 偏光状態の変化の原因となる増幅用ファイバ 1 7 5の周囲環境の変 化を防止することができるので、 安定した波長変換を行うことができる。  In addition, since the amplification fiber 175 is housed in the container 191 having a substantially closed structure, it is possible to prevent a change in the surrounding environment of the amplification fiber 175 which causes a change in the polarization state. As a result, stable wavelength conversion can be performed.
以上により、結果的に、図 7の光増幅部 1 6 1を採用した光源装置によれば、 偏光調整装置や四分の一波長板 (偏光方向変換装置) を、 必ずしも設けなくて も良い。 As described above, as a result, according to the light source device employing the optical amplification unit 16 1 in FIG. 7, It is not always necessary to provide a polarization adjusting device or a quarter-wave plate (polarization direction changing device).
なお、 上記の説明では、 増幅用光ファイバ 1 7 5として、 フォスフェイ卜ガ ラスを主材とする光ファイバを使用したが、 酸化ビスマス系ガラス (B i 203 B 203) を主材とする光ファイバを使用することも可能である。 酸化ビスマス 系ガラスでは、 従来のシリカガラスと比べて、 エルビウムのドープ量を 1 0 0 倍程度以上にすることができ、 フォスフェイ卜ガラスの場合と同様の効果を得 ることができる。 また、 この変形例では、 増幅用ファイバとして E rドープフ アイバを採用したが、 Y bドープファイバその他の希土類元素ドープファイバ を採用することも可能である。 また、 増幅用光導波路部材として光ファイバ型 部材に限らず、 これ以外のもの、 例えば平面型導波路型部材を使用することも 可能である。 Incidentally, the main material in the above description, as an amplification optical fiber 1 7 5, but using an optical fiber for mainly including Fosufei Bokuga lath, bismuth oxide-based glass (B i 2 0 3 B 2 0 3) It is also possible to use an optical fiber. In the bismuth oxide glass, the erbium doping amount can be increased to about 100 times or more as compared with the conventional silica glass, and the same effect as in the case of the phosphate glass can be obtained. In this modification, an Er-doped fiber is used as the amplification fiber, but a Yb-doped fiber or another rare-earth element-doped fiber may be used. Further, the amplifying optical waveguide member is not limited to the optical fiber type member, but other members, for example, a planar waveguide type member can be used.
また、 上記実施形態中では特に説明をしなかったが、 本実施形態のように、 1 9 3 n m以下の露光波長により露光を行う装置の場合には、 光束通過部分に はケミカルフィルタを通過したクリーンエアーや、 ドライエアー、 N 2ガス、 若 しくはヘリウム、 アルゴン、 クリプトン等の不活性ガスを充填させあるいはフ ローさせたり、 該光束通過部分を真空にする等の処置が必要となる。 Although not specifically described in the above embodiment, in the case of an apparatus that performs exposure with an exposure wavelength of 193 nm or less as in this embodiment, a light beam passing portion passes through a chemical filter. clean air and dry air, N 2 gas, young properly helium, argon, or to be allowed or flow filled with an inert gas krypton, becomes the light beam passage portion requires treatment true empty like.
上記実施形態の露光装置は、 本願の特許請求の範囲に挙げられた各構成要素 を含む各種サブシステムを、 所定の機械的精度、 電気的精度、 光学的精度を保 つように、 組み立てることで製造される。 これら各種精度を確保するために、 この組み立ての前後には、 照明光学系 1 2や投影光学系 P L等の各種光学系に ついては光学的精度を達成するための調整(例えば、 光軸合わせ)、各種機械系 については機械的精度を達成するための調整、 各種電気系については電気的精 度を達成するための調整が行われる。 このうち、 各種光学系の特性の調整にあ たっては、 調整用 (検査用) 光源装置として高出力を必要としないので、 上述 の光源装置 1 6において、 1つあるいは少数のファイバ増幅器 1 6 7を含むよ うに簡略化した光源装置を使用することができる。 かかる場合には、 露光光の 波長とほぼ同一の波長の光を簡易に発生し、調整に使用することができるので、 精度の良い調整を簡易な構成で低価格の光源装置によって行うことができる。 なお、 ファイバ増幅器 1 6 7を 1つのみ含むように簡略化するときは、 分岐及 び遅延部 1 6 7も不要となる。 The exposure apparatus of the above-described embodiment is constructed by assembling various subsystems including the respective components listed in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Manufactured. Before and after this assembly, various optical systems such as the illumination optical system 12 and the projection optical system PL are adjusted to achieve optical accuracy (for example, optical axis alignment) before and after this assembly. Various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are adjusted to achieve electrical accuracy. Of these, in adjusting the characteristics of various optical systems, a high output is not required as a light source device for adjustment (for inspection), so one or a small number of fiber amplifiers 16 7 Including A light source device simplified as described above can be used. In such a case, light having a wavelength substantially the same as the wavelength of the exposure light can be easily generated and used for adjustment, so that accurate adjustment can be performed by a low-cost light source device with a simple configuration. . When simplifying to include only one fiber amplifier 167, the branching and delay unit 167 is also unnecessary.
各種サブシステムから露光装置への組み立て工程は、 各種サブシステム相互 の、 機械的接続、 電気回路の配線接続、 気圧回路の配管接続等が含まれる。 こ の各種サブシステムから露光装置への組み立て工程の前に、 各サブシステム 個々の組み立て工程があることは言うまでもない。 各種サブシステムの露光装 置への組み立て工程が終了したら、 総合調整が行われ、 露光装置全体としての 各種精度が確保される。 かかる総合調整においても、 必要に応じて上記の簡略 化した光源装置を使用することができる。 なお、 露光装置の製造は温度および クリーン度等が管理されたクリーンルームで行うことが望ましい。  The process of assembling the exposure apparatus from various subsystems includes mechanical connections, wiring connections of electric circuits, and piping connections of pneumatic circuits among the various subsystems. It goes without saying that there is an individual assembly process for each subsystem before the assembly process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure equipment is completed, comprehensive adjustments are made to ensure various precisions of the entire exposure equipment. In such an overall adjustment, the above-described simplified light source device can be used if necessary. It is desirable that the exposure apparatus be manufactured in a clean room where the temperature, cleanliness, etc. are controlled.
また、 上記実施形態では、 本発明に係る光源装置が露光用照明光を発生する 光源装置として使用される例を説明したが、 露光用照明光とほぼ同一の波長の 光を必要とする上述のレチクルァライメン卜用の光源装置として使用すること も可能である。 この場合には、 上述の簡略化された光源装置を使用することは 勿論である。  Further, in the above-described embodiment, an example in which the light source device according to the present invention is used as a light source device that generates illumination light for exposure has been described. It can also be used as a light source device for reticle alignment. In this case, it goes without saying that the above-described simplified light source device is used.
また、 上記実施形態では、 本発明に係る光源装置がステップ ·アンド ·スキ ヤン方式の走査型露光装置に適用された場合について説明したが、 露光装置以 外の装置、例えば、 ウェハ上に形成された回路パターンの一部(ヒューズなど) を切断するために用いられるレーザリペア装置などにも本発明に係る光源装置 を適用することができる。 また、 本発明に係る光源装置は可視光または赤外光 を用いる検査装置などにも適用することができる。 そしてこの場合には前述の 波長変換部を光源装置に組み込む必要がない。 すなわち、 本発明は紫外レーザ 装置だけでなく、 可視域または赤外域の基本波を発生する、 波長変換部がない レーザ装置に対しても有効なものである。 Further, in the above embodiment, the case where the light source device according to the present invention is applied to a step-and-scan type scanning exposure apparatus has been described. However, the light source apparatus is formed on an apparatus other than the exposure apparatus, for example, a wafer. The light source device according to the present invention can also be applied to a laser repair device used for cutting a part of a circuit pattern (such as a fuse). Further, the light source device according to the present invention can be applied to an inspection device using visible light or infrared light. In this case, it is not necessary to incorporate the above-mentioned wavelength converter into the light source device. That is, the present invention is not limited to an ultraviolet laser device, and does not include a wavelength conversion unit that generates a fundamental wave in the visible or infrared region. This is also effective for a laser device.
さらに、 露光装置以外の装置、 例えば光学式検査装置等における光源装置と しても、 本発明の光源装置は利用可能である。 また、 眼底に紫外光を照射して 視力矯正を行う装置などの光源装置としても利用可能であり、 さらにはエキシ マレーザが適用される各種装置でも、 本発明の光源装置は利用可能である。 また、 本発明は、 ステップ ·アンド ·スキャン方式の走査型露光装置に限ら ず、 静止露光型、 例えばステップ 'アンド, リピート方式の露光装置 (ステツ パなど) にも好適に適用できるものである。 更にはステップ ·アンド ·スティ ツチ方式の露光装置、 ミラープロジェクシヨン ·ァライナーなどにも適用でき る。  Further, the light source device of the present invention can be used as a light source device in an apparatus other than the exposure apparatus, for example, an optical inspection apparatus. Further, the light source device of the present invention can also be used as a light source device such as a device that corrects vision by irradiating the fundus with ultraviolet light, and various devices to which an excimer laser is applied. In addition, the present invention is not limited to a step-and-scan type scanning exposure apparatus, but can be suitably applied to a stationary exposure type, for example, an exposure apparatus (eg, a stepper) of a step-and-repeat type. Further, the present invention can be applied to a step-and-stitch type exposure apparatus, a mirror projection aligner, and the like.
なお、 上記実施形態で示した投影光学系や、 照明光学系はほんの一例であつ て、 本発明がこれに限定されないことは勿論である。 例えば、 投影光学系とし て屈折光学系に限らず、 反射光学素子のみからなる反射系、 又は反射光学素子 と屈折光学素子とを有する反射屈折系 (力タツディオプ卜リック系) を採用し ても良い。 波長 2 0 0 n m程度以下の真空紫外光 (V U V光) を用いる露光装 置では、 投影光学系として反射屈折系を用いることも考えられる。 この反射屈 折型の投影光学系としては、 例えば特開平 8— 1 7 1 0 5 4号公報及びこれに 対応する米国特許第 5, 6 6 8 , 6 7 2号、 並びに特開平 1 0— 2 0 1 9 5号 公報及びこれに対応する米国特許第 5, 8 3 5, 2 7 5号などに開示される、 反射光学素子としてビームスプリッタと凹面鏡とを有する反射屈折系、 又は特 開平 8— 3 3 4 6 9 5号公報及びこれに対応する米国特許第 5, 6 8 9, 3 7 7号、 並びに特開平 1 0— 3 0 3 9号公報及びこれに対応する米国特許出願第 8 7 3, 6 0 5号 (出願日 : 1 9 9 7年 6月 1 2日) などに開示される、 反射 光学素子としてビームスプリッタを用いずに凹面鏡などを有する反射屈折系を 用いることができる。 本国際出願で指定した指定国又は選択した選択国の国内 法令が許す限りにおいて、 上記各公報及びこれらに対応する米国特許、 及び米 国特許出願における開示を援用して本明細書の記載の一部とする。 Note that the projection optical system and the illumination optical system described in the above embodiments are merely examples, and it is a matter of course that the present invention is not limited to these. For example, the projection optical system is not limited to the refractive optical system, but may be a reflective system composed of only a reflective optical element, or a catadioptric system having a reflective optical element and a refractive optical element (power dioptric system). . In an exposure apparatus that uses vacuum ultraviolet light (VUV light) having a wavelength of about 200 nm or less, a catadioptric system may be used as the projection optical system. Examples of the reflection bending type projection optical system include, for example, Japanese Patent Application Laid-Open No. Hei 8-171504 and US Patent Nos. 5,668,672 corresponding thereto, and Japanese Patent Application Laid-Open No. A catadioptric system having a beam splitter and a concave mirror as a reflective optical element, or a catadioptric system disclosed in US Pat. No. 2,195,955 and corresponding US Pat. Nos. 5,835,275. — 3 3 4 6 9 5 and the corresponding US Pat. No. 5,689, 3777, and Japanese Patent Application Laid-Open No. 10-309 39 and the corresponding US patent application No. 8 A catadioptric system having a concave mirror or the like can be used as a reflecting optical element without using a beam splitter as disclosed in JP 73,605 (filing date: June 12, 1997) . To the extent permitted by the national laws of the designated or designated elected States in this International Application, the above publications and their corresponding U.S. patents and The disclosure in the national patent application is incorporated herein by reference.
この他、 米国特許第 5 , 4 8 8, 2 2 9号、 及び特開平 1 0— 1 0 4 5 1 3 号公報に開示される、 複数の屈折光学素子と 2枚のミラー (凹面鏡である主鏡 と、 屈折素子又は平行平面板の入射面と反対側に反射面が形成される裏面鏡で ある副鏡) とを同一軸上に配置し、 その複数の屈折光学素子によって形成され るレチクルパターンの中間像を、 主鏡と副鏡とによってウェハ上に再結像させ る反射屈折系を用いても良い。 この反射屈折系では、 複数の屈折光学素子に続 けて主鏡と副鏡とが配置され、 照明光が主鏡の一部を通って副鏡、 主鏡の順に 反射され、 さらに副鏡の一部を通ってウェハ上に達することになる。 本国際出 願で指定した指定国又は選択した選択国の国内法令が許す限りにおいて、 上記 米国特許における開示を援用して本明細書の記載の一部とする。  In addition, a plurality of refractive optical elements and two mirrors (concave mirrors) are disclosed in U.S. Pat. No. 5,488,229 and Japanese Patent Application Laid-Open No. H10-1040513. A reticle formed by a plurality of refractive optical elements, in which a primary mirror and a sub-mirror, which is a back-side mirror having a reflective surface formed on the side opposite to the incident surface of the refractive element or the plane-parallel plate, are arranged on the same axis. A catadioptric system that re-images the intermediate image of the pattern on the wafer by the primary mirror and the secondary mirror may be used. In this catadioptric system, a primary mirror and a secondary mirror are arranged following a plurality of refractive optical elements, and the illumination light passes through a part of the primary mirror and is reflected in the order of the secondary mirror and the primary mirror. It will reach the wafer through a portion. To the extent permitted by the national laws of the designated or designated elected country in this international application, the disclosures in the above US patents will be incorporated by reference into this description.
また、 上記実施形態では、 オプティカルインテグレータ (ホモジナイザ) と してフライアイレンズ系を用いるものとしたが、 その代わリにロッド ·インテ グレータを用いるようにしてもよい。 ロッド ·インテグレータを用いる照明光 学系では、 ロッド,インテグレータはその射出面がレチクル Rのパターン面と ほぼ共役になるように配置されるので、 例えばロッド ·インテグレー夕の射出 面に近接して前述の固定レチクルブラインド 3 0 Aや可動レチクルプラインド 3 0 Bを配置しても良い。  In the above embodiment, a fly-eye lens system is used as an optical integrator (homogenizer). However, a rod integrator may be used instead. In an illumination optics system using a rod integrator, the rod and integrator are arranged so that their exit surface is almost conjugate to the pattern surface of the reticle R. A fixed reticle blind 30 A or a movable reticle blind 30 B may be provided.
勿論、 半導体素子の製造に用いられる露光装置だけでなく、 液晶表示素子な どを含むディスプレイの製造に用いられる、 デバイスパターンをガラスプレー 卜上に転写する露光装置、 薄膜磁気ヘッドの製造に用いられる、 デバイスバタ ーンをセラミックウェハ上に転写する露光装置、及び撮像素子(C C Dなど)、 マイクロマシン、 D N Aチップの製造、 さらにはレチクルやマスクの製造など に用いられる露光装置などにも本発明を適用することができる。  Of course, it is used not only for the exposure equipment used for manufacturing semiconductor devices, but also for the manufacture of displays including liquid crystal display elements, etc., and is used for the manufacture of thin film magnetic heads and exposure equipment for transferring device patterns onto glass plates. The present invention is also applicable to an exposure apparatus that transfers device patterns onto a ceramic wafer, and an exposure apparatus that is used for manufacturing an imaging device (such as a CCD), a micromachine, a DNA chip, and further, for manufacturing a reticle or a mask. can do.
《デバイス製造方法》  《Device manufacturing method》
次に、 上述した露光装置及び露光方法をリソダラフィ工程で使用したデバィ スの製造方法の実施形態について説明する。 Next, a device using the above-described exposure apparatus and exposure method in a lithography process. An embodiment of a method for manufacturing a metal will be described.
図 8には、 デバイス ( I Cや L S I等の半導体チップ、 液晶パネル、 C C D、 薄膜磁気ヘッド、 マイクロマシン等) の製造例のフローチャートが示されてい る。 図 8に示されるように、 まず、 ステップ 2 0 1 (設計ステップ) において、 デバイスの機能 ·性能設計 (例えば、 半導体デバイスの回路設計等) を行い、 その機能を実現するためのパターン設計を行う。引き続き、ステップ 2 0 2 (マ スク製作ステップ) において、 設計した回路パターンを形成したマスクを製作 する。 一方、 ステップ 2 0 3 (ウェハ製造ステップ) において、 シリコン等の 材料を用いてウェハを製造する。  FIG. 8 shows a flowchart of an example of manufacturing devices (semiconductor chips such as IC and LSI, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). As shown in FIG. 8, first, in step 201 (design step), a function and performance design of a device (for example, a circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. . Subsequently, in step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.
次に、 ステップ 2 0 4 (ウェハ処理ステップ) において、 ステップ 2 0 1 〜 ステップ 2 0 3で用意したマスクとウェハを使用して、 後述するように、 リソ グラフィ技術等によってウェハ上に実際の回路等を形成する。 次いで、 ステツ プ 2 0 5 (デバイス組立ステップ) において、 ステップ 2 0 4で処理されたゥ ェハを用いてデバイス組立を行う。このステップ 2 0 5には、ダイシング工程、 ボンディング工程、 及びパッケージング工程 (チップ封入) 等の工程が必要に 応じて含まれる。  Next, in step 204 (wafer processing step), using the mask and the wafer prepared in steps 201 to 203, an actual circuit is formed on the wafer by lithography technology or the like as described later. Etc. are formed. Next, in step 205 (device assembling step), device assembly is performed using the wafer processed in step 204. Step 205 includes, as necessary, processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation).
最後に、 ステップ 2 0 6 (検査ステップ) において、 ステップ 2 0 5で作製 されたデバイスの動作確認テス卜、 耐久性テス卜等の検査を行う。 こうしたェ 程を経た後にデバイスが完成し、 これが出荷される。  Finally, in step 206 (inspection step), an operation check test, a durability test, and the like of the device manufactured in step 205 are performed. After these steps, the device is completed and shipped.
図 9には、 半導体デバイスの場合における、 上記ステップ 2 0 4の詳細なフ ロー例が示されている。 図 9において、 ステップ 2 1 1 (酸化ステップ) にお いてはウェハの表面を酸化させる。 ステップ 2 1 2 ( C V Dステップ) におい てはウェハ表面に絶縁膜を形成する。 ステップ 2 1 3 (電極形成ステップ) に おいてはウェハ上に電極を蒸着によって形成する。 ステップ 2 1 4 (イオン打 込みステップ) においてはウェハにイオンを打ち込む。 以上のステップ 2 1 1 〜ステップ 2 1 4それぞれは、 ウェハ処理の各段階の前処理工程を構成してお り、 各段階において必要な処理に応じて選択されて実行される。 FIG. 9 shows a detailed flow example of the above step 204 in the case of a semiconductor device. In FIG. 9, in step 2 11 (oxidation step), the surface of the wafer is oxidized. In step 2 1 (CVD step), an insulating film is formed on the wafer surface. In step 2 13 (electrode formation step), electrodes are formed on the wafer by vapor deposition. In step 2 14 (ion implantation step), ions are implanted into the wafer. Each of the above steps 211 to 2114 constitutes a pretreatment process at each stage of wafer processing. In each stage, it is selected and executed according to the required processing.
ウェハプロセスの各段階において、 上述の前処理工程が終了すると、 以下の ようにして後処理工程が実行される。 この後処理工程では、 まず、 ステップ 2 1 5 (レジス卜形成ステップ) において、 ウェハに感光剤を塗布する。 引き続 き、 ステップ 2 1 6 (露光ステップ) において、 上で説明した露光装置 1 0を 用いてマスクの回路パターンをウェハに転写する。 次に、 ステップ 2 1 7 (現 像ステップ) においては露光されたウェハを現像し、 ステップ 2 1 8 (エッチ ングステップ) において、 レジス卜が残存している部分以外の部分の露出部材 をエッチングにより取り去る。 そして、 ステップ 2 1 9 (レジス卜除去ステツ プ) において、 エッチングが済んで不要となったレジス卜を取り除く。  In each stage of the wafer process, when the above-described pre-processing step is completed, the post-processing step is executed as follows. In this post-processing step, first, in step 2 15 (register forming step), a photosensitive agent is applied to the wafer. Subsequently, in step 2 16 (exposure step), the circuit pattern of the mask is transferred onto the wafer by using the exposure apparatus 10 described above. Next, in Step 217 (imaging step), the exposed wafer is developed, and in Step 218 (etching step), the exposed members other than the portion where the resist remains are etched. Remove it. Then, in step 219 (registry removal step), unnecessary resist after etching is removed.
これらの前処理工程と後処理工程とを繰り返し行うことによって、 ウェハ上 に多重に回路パターンが形成される。  By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.
以上説明した本実施形態のデバイス製造方法によると、 露光工程 (ステップ 2 1 6 ) において上記実施形態の露光装置 1 0及びその露光方法を用いて露光 が行われるので、 露光精度の向上により、 高集積度のデバイスを歩留まり良く 生産することができる。 産業上の利用可能性  According to the device manufacturing method of the present embodiment described above, exposure is performed using the exposure apparatus 10 of the above embodiment and the exposure method in the exposure step (step 2 16). Devices with a high degree of integration can be produced with high yield. Industrial applicability
以上説明したように、 本発明の光源装置は、 高精度な光量制御を行うのに適 している。 また、 本発明の波長安定化制御方法は、 レーザ光の中心波長を所定 の設定波長に設定維持するのに適している。 また、 本発明の露光装置及び露光 方法は、集積回路等のマイクロデバイスを製造するリソグラフイエ程において、 微細パターンをウェハ等の基板上に精度良く形成するのに適している。 また、 本発明に係るデバイス製造方法は、 微細なパターンを有するデバイスの製造に 適している。  As described above, the light source device of the present invention is suitable for performing highly accurate light quantity control. Further, the wavelength stabilization control method of the present invention is suitable for setting and maintaining the center wavelength of laser light at a predetermined set wavelength. Further, the exposure apparatus and the exposure method of the present invention are suitable for forming a fine pattern on a substrate such as a wafer with high precision in a lithographic process for manufacturing a micro device such as an integrated circuit. Further, the device manufacturing method according to the present invention is suitable for manufacturing a device having a fine pattern.

Claims

請 求 の 範 囲 The scope of the claims
1 . 単一波長の光を発生する光源装置であって、  1. A light source device for generating light of a single wavelength,
単一波長の光を発生する光発生部と;  A light generator for generating light of a single wavelength;
前記光発生部の出力段に並列に配置された複数の光ファイバから成るフアイ バ群と;  A fiber group consisting of a plurality of optical fibers arranged in parallel at an output stage of the light generating unit;
前記各光ファイバからの光出力を個別にオン ·オフすることにより前記ファ ィバ群から出力される光の光量を制御する光量制御装置と;を備える光源装置。  A light amount control device that controls the light amount of light output from the fiber group by individually turning on and off the light output from each of the optical fibers.
2 . 請求項 1 に記載の光源装置において、 2. The light source device according to claim 1,
前記ファイバ群を構成する前記複数の光ファイバは、 それぞれの少なくとも 出力端部が束ねられてバンドル一ファイバが構成されていることを特徴とする 光源装置。  The light source device, wherein each of the plurality of optical fibers constituting the fiber group has at least an output end bundled to form a bundle fiber.
3 . 請求項 1 に記載の光源装置において、  3. The light source device according to claim 1,
前記各光ファイバを含んで構成される各光経路の一部には、 光増幅を行うこ とができるフアイバ増幅器が少なくとも 1段設けられ、  At least one fiber amplifier that can perform optical amplification is provided in a part of each optical path including the optical fibers,
前記光量制御装置は、 前記各光ファイバからの前記光出力のオン ·オフを前 記フアイバ増幅器の励起用光源からの励起光の強度の切リ換えにより行うこと を特徴とする光源装置。  A light source device, wherein the light quantity control device switches on and off the optical output from each of the optical fibers by switching the intensity of excitation light from the excitation light source of the fiber amplifier.
4 . 請求項 3に記載の光源装置において、  4. The light source device according to claim 3,
前記光量制御装置は、 前記励起用光源からの励起光の強度を所定レベルと零 レベルとのいずれかに択一的に設定することにより前記励起光の強度の切り換 えを行うことを特徴とする光源装置。  The light quantity control device switches the intensity of the excitation light by selectively setting the intensity of the excitation light from the excitation light source to one of a predetermined level and a zero level. Light source device.
5 . 請求項 4に記載の光源装置において、  5. The light source device according to claim 4,
前記光量制御装置は、 前記励起用光源をオン,オフすることにより、 前記励 起光の強度を所定レベルと零レベルとのいずれかに択一的に設定することを特 徴とする光源装置。 A light source device characterized in that the light amount control device sets the intensity of the excitation light to one of a predetermined level and a zero level by turning on and off the excitation light source.
6 . 請求項 3に記載の光源装置において、 6. The light source device according to claim 3,
前記光量制御装置は、 前記励起用光源からの励起光の強度を所定の第 1 レべ ルと該第 1 レベルより小さい第 2レベルとのいずれかに択一的に設定すること により前記励起光の強度の切り換えを行うことを特徴とする光源装置。  The light quantity control device may set the intensity of the excitation light from the excitation light source to one of a predetermined first level and a second level smaller than the first level. A light source device for switching the intensity of light.
7 . 請求項 3に記載の光源装置において、  7. The light source device according to claim 3,
前記各光経路には、 前記ファイバ増幅器が複数段設けられ、  In each of the optical paths, the fiber amplifier is provided in a plurality of stages,
前記光量制御装置は、 前記各光ファイバからの前記光出力のオン ·オフを最 終段のフアイバ増幅器の励起用光源からの励起光の強度の切リ換えにより行う ことを特徴とする光源装置。  The light source device, wherein the light quantity control device switches on / off the light output from each of the optical fibers by switching the intensity of excitation light from an excitation light source of a final stage fiber amplifier.
8 . 請求項 7に記載の光源装置において、  8. The light source device according to claim 7,
前記最終段の前記ファイバ増幅器は、 他の段のファイバ増幅器に比べてモー ドフィールド径が大きいことを特徴とする光源装置。  The light source device, wherein the fiber amplifier of the last stage has a larger mode field diameter than the fiber amplifiers of the other stages.
9 . 請求項 1に記載の光源装置において、  9. The light source device according to claim 1,
前記各光ファイバからの光出力のオン ·オフ状況に対応する出力強度マップ が予め記憶された記憶装置を更に備え、  Further comprising a storage device in which an output intensity map corresponding to the ON / OFF state of the optical output from each of the optical fibers is stored in advance,
前記光量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前 記各光ファイバからの光出力を個別にオン ·オフすることを特徴とする光源装 置。  The light source device, wherein the light amount control device individually turns on / off the light output from each optical fiber based on the output intensity map and a predetermined set light amount.
1 0 . 請求項 9に記載の光源装置において、  10. The light source device according to claim 9,
前記出力強度マップは、 予め測定された各ファイバ出力のばらつきに基づい て作成されていることを特徴とする光源装置。  The light source device according to claim 1, wherein the output intensity map is created based on a variation of each fiber output measured in advance.
1 1 . 請求項 9に記載の光源装置において、 11. The light source device according to claim 9,
前記各光ファイバから出力される前記光の波長を変換する波長変換部を更に 備え、  Further comprising a wavelength converter for converting the wavelength of the light output from each of the optical fibers,
前記出力強度マップは、 予め測定された前記各ファイバ出力に対応する波長 変換効率のばらつきに起因する出力のばらつきを更に考慮して作成されている ことを特徴とする光源装置。 The output intensity map is created by further considering a variation in output due to a variation in wavelength conversion efficiency corresponding to each fiber output measured in advance. A light source device characterized by the above-mentioned.
1 2 . 請求項 1 1に記載の光源装置において、  12. The light source device according to claim 11,
前記光発生部は、 赤外域から可視域までの範囲内の単一波長のレーザ光を発 生し、  The light generation unit generates a laser beam having a single wavelength within a range from an infrared region to a visible region,
前記波長変換部は、 前記レーザ光の高調波である紫外光を出力することを特 徴とする光源装置。  The light source device, wherein the wavelength converter outputs ultraviolet light that is a harmonic of the laser light.
1 3 . 請求項 1 2に記載の光源装置において、  13. The light source device according to claim 12,
前記光発生部は、 波長 1 . 5 t m付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 m付近の前記レーザ光の 8倍高調波及 び 1 0倍高調波のいずれかを発生することを特徴とする光源装置。  The light generating section generates a single-wavelength laser light having a wavelength of about 1.5 tm, and the wavelength converting section generates an 8th harmonic and a 10th harmonic of the laser light having a wavelength of about 1.5 m. A light source device for generating one of waves.
1 4 . 請求項 1に記載の光源装置において、  14. The light source device according to claim 1,
前記各光ファイバから出力される前記光の波長を変換する波長変換部を更に 備えることを特徴とする光源装置。  A light source device, further comprising a wavelength conversion unit that converts a wavelength of the light output from each of the optical fibers.
1 5 . 請求項 1 4に記載の光源装置において、  15. The light source device according to claim 14, wherein
前記光発生部は、 赤外域から可視域までの範囲内の単一波長のレーザ光を発 生し、  The light generation unit generates a laser beam having a single wavelength within a range from an infrared region to a visible region,
前記波長変換部は、 前記レーザ光の高調波である紫外光を出力することを特 徴とする光源装置。  The light source device, wherein the wavelength converter outputs ultraviolet light that is a harmonic of the laser light.
1 6 . 請求項 1 5に記載の光源装置において、  16. The light source device according to claim 15,
前記光発生部は、 波長 1 . 5 付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 m付近の前記レーザ光の 8倍高調波及 0倍高調波のいずれかを発生することを特徴とする光源装置。  The light generating section generates a single-wavelength laser light having a wavelength of about 1.5, and the wavelength converting section generates an 8th harmonic and a 0th harmonic of the laser light having a wavelength of about 1.5 m. A light source device that generates
1 7 . 請求項 1に記載の光源装置において、  17. The light source device according to claim 1,
前記光発生部は、 単一波長の光を発生する光源と、 前記光源からの光を所定 周波数のパルス光に変換して出力する光変調器とを有し、  The light generation unit has a light source that generates light of a single wavelength, and an optical modulator that converts light from the light source into pulsed light of a predetermined frequency and outputs the light.
前記光量制御装置は、 前記光変調器から出力されるパルス光の周波数及びピ ークパワーの少なくとも一方を更に制御することを特徴とする光源装置。 The light quantity control device may control a frequency and a peak of the pulse light output from the optical modulator. A light source device for further controlling at least one of the peak powers.
1 8 . 請求項 1 に記載の光源装置において、  18. The light source device according to claim 1,
前記複数の光ファイバそれぞれからの光出力を個別に遅延させて、 前記光出 力を時間的にずらして行わせる遅延部を更に備えることを特徴とする光源装置。 The light source device further includes a delay unit that individually delays the light output from each of the plurality of optical fibers and performs the light output with a time lag.
1 9 . 請求項 1 に記載の光源装置において、 1 9. The light source device according to claim 1,
前記光発生部は、 レーザ光を発振するレーザ光源を有し、  The light generation unit has a laser light source that oscillates laser light,
前記レーザ光の中心波長を所定の設定波長に維持するための波長安定化に関 連する前記レーザ光の光学特性をモニタするビームモニタ機構と;  A beam monitoring mechanism for monitoring optical characteristics of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined wavelength;
前記ビームモニタ機構の検出基準波長の温度依存性のデータに基づいて、 波 長キヤリプレーションを行う波長キヤリプレーション制御装置と;を更に備え ることを特徴とする光源装置。  A wavelength calibration controller that performs wavelength calibration based on data on the temperature dependence of the detection reference wavelength of the beam monitoring mechanism.
2 0 . 請求項 1 9に記載の光源装置において、 20. The light source device according to claim 19,
前記複数の光ファイバを介した同一波長の複数の光束の偏光状態を揃える偏 光調整装置と;  A polarization adjusting device for aligning the polarization states of a plurality of light beams of the same wavelength via the plurality of optical fibers;
前記複数の光ファイバを介した全ての光束を同一の偏光方向を有する複数の 直線偏光光束に変換する偏光方向変換装置と;を更に備えることを特徴とする 光源装置。  A polarization direction conversion device that converts all the light beams transmitted through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
2 1 . 請求項 2 0に記載の光源装置において、  21. The light source device according to claim 20,
前記各光ファイバを含んで構成される各光経路の一部には、 光増幅を行うこ とができるフアイバ増幅器が少なくとも 1段設けられ、  At least one fiber amplifier that can perform optical amplification is provided in a part of each optical path including the optical fibers,
前記ファイバ増幅器は、 希土類元素が添加されたフォスフェイ卜ガラス及び 酸化ビスマス系ガラスのいずれかを主材とする光ファイバを光導波路部材とし て有することを特徴とする光源装置。  The light source device according to claim 1, wherein the fiber amplifier includes, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
2 2 . 単一波長の光を発生する光源装置であって、 2 2. A light source device for generating light of a single wavelength,
単一波長の光を発生する光源と、 該光源からの光を所定周波数のパルス光に 変換して出力する光変調器とを有する光発生部と; 前記光発生部によって発生されたパルス光を増幅する少なくとも 1段のファ ィバ増幅器を含む光増幅部と; A light generator having a light source that generates light of a single wavelength, and an optical modulator that converts light from the light source into pulsed light of a predetermined frequency and outputs the pulsed light; An optical amplification unit including at least one fiber amplifier for amplifying the pulsed light generated by the light generation unit;
前記光変調器から出力される前記パルス光の周波数を制御することにより前 記ファイバ増幅器からの出力光の光量を制御する光量制御装置と;を備える光  A light amount control device that controls the light amount of the output light from the fiber amplifier by controlling the frequency of the pulse light output from the optical modulator.
2 3 . 請求項 2 2に記載の光源装置において、 23. In the light source device according to claim 22,
前記光増幅部に入力するパルス光の周波数に応じた前記光増幅部の出力強度 マップが記憶された記憶装置を更に備え、  Further comprising a storage device in which an output intensity map of the optical amplification unit according to the frequency of the pulse light input to the optical amplification unit is stored,
前記光量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前 記光変調器から出力される前記パルス光の周波数を制御することを特徴とする 光源装置。  The light source device, wherein the light amount control device controls a frequency of the pulse light output from the optical modulator based on the output intensity map and a predetermined set light amount.
2 4 . 請求項 2 2に記載の光源装置において、  24. In the light source device according to claim 22,
前記光量制御装置は、 前記光変調器から出力される前記パルス光のピークパ ヮーを更に制御することを特徴とする光源装置。  The light source device, wherein the light amount control device further controls a peak power of the pulse light output from the optical modulator.
2 5 . 請求項 2 2に記載の光源装置において、 25. In the light source device according to claim 22,
前記光変調器は、 電気光学変調器であり、  The light modulator is an electro-optic modulator;
前記光量制御装置は、 前記光変調器に印加する電圧パルスの周波数を制御す ることにより、 前記パルス光の周波数を制御することを特徴とする光源装置。  The light source device, wherein the light amount control device controls a frequency of the pulse light by controlling a frequency of a voltage pulse applied to the optical modulator.
2 6 . 請求項 2 2に記載の光源装置において、 26. In the light source device according to claim 22,
前記光増幅部は複数並列に設けられ、  A plurality of the optical amplification units are provided in parallel,
前記各光増幅部の光出力端部は光ファイバによりそれぞれ構成されているこ とを特徴とする光源装置。  A light source device, wherein an optical output end of each of the optical amplifiers is constituted by an optical fiber.
2 7 . 請求項 2 6に記載の光源装置において、  27. The light source device according to claim 26,
前記複数の光増幅部をそれぞれ構成する前記複数の光ファイバは、 束ねられ てバンドル一ファイバが構成されていることを特徴とする光源装置。  The light source device, wherein the plurality of optical fibers constituting each of the plurality of optical amplifiers are bundled to form one bundle fiber.
2 8 . 請求項 2 2に記載の光源装置において、 前記光増幅部から出力される光の波長を変換する波長変換部を更に備えるこ とを特徴とする光源装置。 28. In the light source device according to claim 22, The light source device further includes a wavelength conversion unit that converts a wavelength of light output from the optical amplification unit.
2 9 . 請求項 2 8に記載の光源装置において、  29. The light source device according to claim 28,
前記光発生部は、 赤外域から可視域までの範囲内の単一波長のレーザ光を発 生し、  The light generation unit generates a laser beam having a single wavelength within a range from an infrared region to a visible region,
前記波長変換部は、 前記レーザ光の高調波である紫外光を出力することを特 徴とする光源装置。  The light source device, wherein the wavelength converter outputs ultraviolet light that is a harmonic of the laser light.
3 0 . 請求項 2 9に記載の光源装置において、  30. The light source device according to claim 29,
前記光発生部は、 波長 1 . 5 付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 t m付近の前記レーザ光の 8倍高調波及 び 1 0倍高調波のいずれかを発生することを特徴とする光源装置。  The light generating section generates a single-wavelength laser light having a wavelength of about 1.5, and the wavelength converting section generates an 8th harmonic and a 10th harmonic of the laser light having a wavelength of about 1.5 tm. A light source device that generates any one of the following.
3 1 . 単一波長の光を発生する光源装置であって、 3 1. A light source device for generating light of a single wavelength,
単一波長の光を発生する光源と、 該光源からの光を所定周波数のパルス光に 変換して出力する光変調器とを有する光発生部と;  A light generator having a light source that generates light of a single wavelength, and an optical modulator that converts light from the light source into pulsed light of a predetermined frequency and outputs the pulsed light;
前記光発生部によって発生されたパルス光を増幅する少なくとも 1段のファ ィバ増幅器を含む光増幅部と;  An optical amplification unit including at least one fiber amplifier for amplifying the pulsed light generated by the light generation unit;
前記光変調器から出力される前記パルス光のピークパワーを制御することに より前記光増幅部からの出力光の光量を制御する光量制御装置と;を備える光  A light amount control device that controls a light amount of the output light from the optical amplifying unit by controlling a peak power of the pulse light output from the optical modulator.
3 2 . 請求項 3 1に記載の光源装置において、 3 2. The light source device according to claim 31,
前記光増幅部に入力するパルス光の強度に応じた前記光増幅部の出力強度マ ップが記憶された記憶装置を更に備え、  A storage device in which an output intensity map of the optical amplifier according to the intensity of the pulse light input to the optical amplifier is stored;
前記光量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前 記光変調器から出力される前記パルス光のピークパワーを制御することを特徴 とする光源装置。  The light source device, wherein the light amount control device controls a peak power of the pulse light output from the optical modulator based on the output intensity map and a predetermined set light amount.
3 3 . 請求項 3 1に記載の光源装置において、 前記光変調器は、 電気光学変調器であり、 33. The light source device according to claim 31, The light modulator is an electro-optic modulator;
前記光量制御装置は、 前記光変調器に印加する電圧パルスのピークレベルを 制御することにより、 前記パルス光のピークパワーを制御することを特徴とす る光源装置。  The light source device, wherein the light amount control device controls a peak power of the pulse light by controlling a peak level of a voltage pulse applied to the optical modulator.
3 4 . 請求項 3 1に記載の光源装置において、  34. In the light source device according to claim 31,
前記光増幅部は複数並列に設けられ、  A plurality of the optical amplification units are provided in parallel,
前記各光増幅部の光出力端部は光ファイバによりそれぞれ構成されているこ とを特徴とする光源装置。  A light source device, wherein an optical output end of each of the optical amplifiers is constituted by an optical fiber.
3 5 . 請求項 3 4に記載の光源装置において、 35. The light source device according to claim 34,
前記複数の光増幅部をそれぞれ構成する前記複数の光ファイバは、 束ねられ てバンドル—ファイバが構成されていることを特徴とする光源装置。  The light source device, wherein the plurality of optical fibers constituting each of the plurality of optical amplifiers are bundled to form a bundle-fiber.
3 6 . 請求項 3 4に記載の光源装置において、 36. In the light source device according to claim 34,
前記複数の光増幅部のそれぞれからの光出力を個別に遅延させて、 前記光出 力を時間的にずらして行わせる遅延部を更に備えることを特徴とする光源装置。  The light source device further comprises a delay unit that individually delays the optical output from each of the plurality of optical amplifiers and shifts the optical output in time.
3 7 . 請求項 3 1に記載の光源装置において、 37. The light source device according to claim 31,
前記光増幅部から出力される光の波長を変換する波長変換部を更に備えるこ とを特徴とする光源装置。  The light source device further includes a wavelength conversion unit that converts a wavelength of light output from the optical amplification unit.
3 8 . 請求項 3 7に記載の光源装置において、  38. In the light source device according to claim 37,
前記光発生部は、 赤外域から可視域までの範囲内の単一波長のレーザ光を発 生し、  The light generation unit generates a laser beam having a single wavelength within a range from an infrared region to a visible region,
前記波長変換部は、 前記レーザ光の高調波である紫外光を出力することを特 徴とする光源装置。  The light source device, wherein the wavelength converter outputs ultraviolet light that is a harmonic of the laser light.
3 9 . 請求項 3 8に記載の光源装置において、  39. In the light source device according to claim 38,
前記光発生部は、 波長 1 . 5 m付近の単一波長のレーザ光を発生し、 前記波長変換部は、 前記波長 1 . 5 m付近の前記レーザ光の 8倍高調波及 び 1 0倍高調波のいずれかを発生することを特徴とする光源装置。 The light generating section generates a single-wavelength laser light having a wavelength of about 1.5 m, and the wavelength converting section generates an 8th harmonic and a 10th harmonic of the laser light having a wavelength of about 1.5 m. A light source device for generating one of waves.
4 0 . 請求項 2 2又は 3 1 に記載の光源装置において、 40. In the light source device according to claim 22 or 31,
前記光発生部は、 前記光源としてレーザ光を発振するレーザ光源を有し、 前記レーザ光の中心波長を所定の設定波長に維持するための波長安定化に関 連する前記レーザ光の光学特性をモニタするビームモニタ機構と;  The light generation unit has a laser light source that oscillates laser light as the light source, and has an optical characteristic of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength. A beam monitoring mechanism for monitoring;
前記ビームモニタ機構の検出基準波長の温度依存性のデータに基づいて、 波 長キヤリブレーションを行う波長キヤリブレーション制御装置と ;を更に備え ることを特徴とする光源装置。  A wavelength calibration controller that performs wavelength calibration based on data on the temperature dependence of the detection reference wavelength of the beam monitoring mechanism.
4 1 . 請求項 4 0に記載の光源装置において、  41. The light source device according to claim 40,
前記光増幅部は、 複数並列に設けられ、  A plurality of the optical amplification units are provided in parallel;
前記複数の光増幅部をそれぞれ構成する前記複数の光ファイバを介した同一 波長の複数の光束の偏光状態を揃える偏光調整装置と ;  A polarization adjusting device for aligning the polarization states of a plurality of light beams having the same wavelength via the plurality of optical fibers constituting the plurality of optical amplification units;
前記複数の光ファイバを介した全ての光束を同一の偏光方向を有する複数の 直線偏光光束に変換する偏光方向変換装置と ;を更に備えることを特徴とする 光源装置。  A polarization direction conversion device that converts all light beams transmitted through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
4 2 . 請求項 4 1 に記載の光源装置において、  42. In the light source device according to claim 41,
前記ファイバ増幅器は、 希土類元素が添加されたフォスフェイ卜ガラス及び 酸化ビスマス系ガラスのいずれかを主材とする光ファイバを光導波路部材とし て有することを特徴とする光源装置。  The light source device according to claim 1, wherein the fiber amplifier includes, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
4 3 . レーザ光を発振するレーザ光源と ; 4 3. A laser light source that oscillates laser light;
前記レーザ光の中心波長を所定の設定波長に維持するための波長安定化に関 連する前記レーザ光の光学特性をモニタするビームモニタ機構と ;  A beam monitoring mechanism for monitoring optical characteristics of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength;
前記ビームモニタ機構の検出基準波長の温度依存性のデータに基づいて、 波 長キャリブレーションを行う第 1の制御装置と ;を備える光源装置。  A first controller that performs wavelength calibration based on data on the temperature dependence of the detection reference wavelength of the beam monitor mechanism.
4 4 . 請求項 4 3に記載の光源装置において、 44. In the light source device according to claim 43,
前記設定波長に近い絶対波長を提供する絶対波長提供源を更に備え、 前記第 1の制御装置は、 前記絶対波長提供源から提供される絶対波長に対し て前記ビームモニタ機構の検出基準波長をほぼ一致させる絶対波長キヤリブレ ーションを行うとともに、 前記温度依存性のデータに基づいて前記検出基準波 長を前記設定波長に一致させる設定波長キャリブレーションを行うことを特徴 とする光源装置。 The apparatus further comprises an absolute wavelength providing source that provides an absolute wavelength close to the set wavelength, wherein the first control device controls an absolute wavelength provided from the absolute wavelength providing source. Performing an absolute wavelength calibration for substantially matching the detection reference wavelength of the beam monitor mechanism, and performing a set wavelength calibration for matching the detection reference wavelength to the set wavelength based on the temperature dependency data. Characteristic light source device.
4 5 . 請求項 4 4に記載の光源装置において、  45. In the light source device according to claim 44,
前記ビームモニタ機構は、 フアプリペロー ·エタロンを含み、  The beam monitoring mechanism includes a pupil perot etalon,
前記温度依存性のデータは、 前記フアプリペロー■エタロンの共鳴波長の温 度依存性の測定結果に基づくデータを含み、  The data of the temperature dependency includes data based on a measurement result of the temperature dependency of the resonance wavelength of the Fluoro-Perot etalon,
前記第 1の制御装置は、 前記ビームモニタ機構を構成する前記フアブリべ口 一 ·エタロンの温度を制御することにより、 前記検出基準波長の前記絶対波長 キヤリブレーション及び前記設定波長キヤリプレーシヨンを行うことを特徴と する光源装置。  The first control device performs the absolute wavelength calibration of the detection reference wavelength and the set wavelength calibration by controlling a temperature of the Fabry-Port-etalon constituting the beam monitoring mechanism. A light source device characterized in that:
4 6 . 請求項 4 4に記載の光源装置において、  46. In the light source device according to claim 44,
前記温度依存性のデータは、 前記レーザ光源から発振される前記レーザ光の 中心波長の温度依存性のデータを更に含み、  The temperature-dependent data further includes temperature-dependent data of a center wavelength of the laser light oscillated from the laser light source,
前記第 1の制御装置は、 前記絶対波長キャリブレーションを行うに際に、 前 記レーザ光源の波長制御をも併せて行うことを特徴とする光源装置。  The light source device, wherein the first control device also performs the wavelength control of the laser light source when performing the absolute wavelength calibration.
4 7 . 請求項 4 4に記載の光源装置において、 47. The light source device according to claim 44, wherein
前記絶対波長提供源は、 前記レーザ光が入射する吸収セルであリ、 前記第 1の制御装置は、 前記絶対波長キャリブレーションを行う際に、 前記 吸収セルの前記設定波長に最も近い吸収線の吸収が最大となり、 かつ前記ファ プリペロー■エタロンの透過率が最大となるようにすることを特徴とする光源  The absolute wavelength providing source is an absorption cell on which the laser light is incident.The first control device, when performing the absolute wavelength calibration, determines an absorption line closest to the set wavelength of the absorption cell. A light source characterized in that absorption is maximized, and transmittance of the Fabry-Perot etalon is maximized.
4 8 . 請求項 4 3に記載の光源装置において、 48. In the light source device according to claim 43,
前記レーザ光源からのレーザ光を増幅するフアイバ増幅器を更に備えること を特徴とする光源装置。 A light source device further comprising a fiber amplifier for amplifying a laser beam from the laser light source.
4 9 . 請求項 4 8に記載の光源装置において、 49. In the light source device according to claim 48,
前記増幅されたレーザ光の波長を変換する非線形光学結晶を含む波長変換器 を更に備えることを特徴とする光源装置。  A light source device, further comprising: a wavelength converter including a nonlinear optical crystal that converts a wavelength of the amplified laser light.
5 0 . 請求項 4 3に記載の光源装置において、  50. The light source device according to claim 43,
前記設定波長キヤリプレーションの終了後に、 前記設定波長キヤリブレーシ ヨンが終了した前記ビームモニタ機構のモニタ結果に基づいて、 前記レーザ光 源からの前記レーザ光の波長をフィードバック制御する第 2の制御装置を更に 備えることを特徴とする光源装置。  After the set wavelength calibration is completed, a second control device that performs feedback control of the wavelength of the laser light from the laser light source based on the monitoring result of the beam monitor mechanism that has completed the set wavelength calibration. A light source device, further comprising:
5 1 . 請求項 4 3に記載の光源装置において、 51. The light source device according to claim 43,
前記レーザ光源の出力段に並列に配置され、 ファイバ増幅器をそれぞれ含む 複数の光増幅部と;  A plurality of optical amplifying units arranged in parallel with an output stage of the laser light source and each including a fiber amplifier;
前記複数の光増幅部をそれぞれ構成する前記複数の光ファイバを介した同一 波長の複数の光束の偏光状態を揃える偏光調整装置と;  A polarization adjusting device for aligning the polarization states of a plurality of light beams of the same wavelength via the plurality of optical fibers respectively configuring the plurality of optical amplification units;
前記複数の光ファイバを介した全ての光束を同一の偏光方向を有する複数の 直線偏光光束に変換する偏光方向変換装置と;を更に備えることを特徴とする 光源装置。  A polarization direction conversion device that converts all the light beams transmitted through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
5 2 . 請求項 5 1に記載の光源装置において、  52. The light source device according to claim 51,
前記ファイバ増幅器は、 希土類元素が添加されたフォスフェイ卜ガラス及び 酸化ビスマス系ガラスのいずれかを主材とする光ファイバを光導波路部材とし て有することを特徴とする光源装置。  The light source device according to claim 1, wherein the fiber amplifier includes, as an optical waveguide member, an optical fiber mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass.
5 3 . 複数の光ファイバと; 5 3. With multiple optical fibers;
前記複数の光ファイバを介した同一波長の複数の光束の偏光状態を揃える偏 光調整装置と;  A polarization adjusting device for aligning the polarization states of a plurality of light beams of the same wavelength via the plurality of optical fibers;
前記複数の光ファイバを介した全ての光束を同一の偏光方向を有する複数の 直線偏光光束に変換する偏光方向変換装置と;を備える光源装置。  A polarization direction conversion device that converts all light beams transmitted through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction.
5 4 . 請求項 5 3に記載の光源装置において、 前記偏光調整装置は、 前記各光ファイバを介した複数の光束それぞれの偏光 状態をほぼ円偏光とし、 54. The light source device according to claim 53, The polarization adjusting device sets the polarization state of each of the plurality of light beams passing through each of the optical fibers to substantially circular polarization,
前記偏光方向変換装置は、 四分の一波長板を有することを特徴とする光源装 置。  The light source device, wherein the polarization direction conversion device has a quarter-wave plate.
5 5 . 請求項 5 4に記載の光源装置において、  55. The light source device according to claim 54, wherein
前記光ファイバはほぼ円筒対称の構造を有し、  The optical fiber has a substantially cylindrically symmetric structure,
前記偏光調整装置は、 前記各光ファイバに入射する複数の光束それぞれの偏 光状態をほぼ円偏光とすることを特徴とする光源装置。  The light source device, wherein the polarization adjusting device sets the polarization state of each of the plurality of light beams incident on each of the optical fibers to substantially circular polarization.
5 6 . 請求項 5 3に記載の光源装置において、 56. In the light source device according to claim 53,
前記偏光調整装置は、 前記各光フアイバを介した複数の光束それぞれの偏光 状態をほぼ同一の楕円偏光とし、  The polarization adjusting device sets the polarization state of each of the plurality of light beams passing through each of the optical fibers to substantially the same elliptically polarized light,
前記偏光方向変換装置は、 偏波面を回転する二分の一波長板と、 前記二分の 一波長板と光学的に直列接続された四分の一波長板とを有することを特徴とす る光源装置。  A light source device comprising: a half-wave plate rotating a plane of polarization; and a quarter-wave plate optically connected in series with the half-wave plate. .
5 7 . 請求項 5 3に記載の光源装置において、  57. The light source device according to claim 53,
前記複数の光ファイバそれぞれは、 前記複数の光ファイバに入射する複数の 光束それぞれを増幅対象光とする光ファイバ増幅器を構成する、 前記増幅対象 光が導波される光ファイバであることを特徴とする光源装置。  Each of the plurality of optical fibers constitutes an optical fiber amplifier that uses a plurality of light beams incident on the plurality of optical fibers as amplification target light, and is an optical fiber through which the amplification target light is guided. Light source device.
5 8 . 請求項 5 4に記載の光源装置において、 58. In the light source device according to claim 54,
前記光ファイバは、 希土類元素が添加されたフォスフェイ卜ガラス及び酸化 ビスマス系ガラスのいずれかを主材として形成されていることを特徴とする光  The optical fiber is formed by using any one of a phosphate glass and a bismuth oxide-based glass to which a rare earth element is added as a main material.
5 9 . 請求項 5 3に記載の光源装置において、 59. In the light source device according to claim 53,
前記複数の光ファイバに入射する前記複数の光束それぞれは、 パルス光列で あることを特徴とする光源装置。  The light source device, wherein each of the plurality of light beams incident on the plurality of optical fibers is a pulse light train.
6 0 . 請求項 5 3に記載の光源装置において、 前記複数の光ファイバに入射する前記複数の光束それぞれは、 前記複数の光 ファイバへ入射する前に 1段以上の光ファイバ増幅器によって増幅された光束 であることを特徴とする光源装置。 60. The light source device according to claim 53, The light source device, wherein each of the plurality of light beams incident on the plurality of optical fibers is a light beam amplified by one or more optical fiber amplifiers before being incident on the plurality of optical fibers.
6 1 . 請求項 5 3に記載の光源装置において、 6 1. The light source device according to claim 53,
前記偏光調整装置は、 前記複数の光ファイバよりも上流側に配置された光学 部品の光特性を制御して偏光調整を行うことを特徴とする光源装置。  The light source device, wherein the polarization adjusting device controls the optical characteristics of optical components disposed upstream of the plurality of optical fibers to adjust the polarization.
6 2 . 請求項 5 3に記載の光源装置において、 6 2. The light source device according to claim 53,
前記複数の光ファイバは、 ほぼ並行に束ねられていることを特徴とする光源  A light source, wherein the plurality of optical fibers are bundled substantially in parallel.
6 3 . 請求項 5 3に記載の光源装置において、 6 3. The light source device according to claim 53,
前記偏光方向変換装置から射出された光束を、 少なくとも 1つの非線形光学 結晶を介させることにより、 波長変換を行う波長変換器を更に備えることを特 徴とする光源装置。  A light source device further comprising a wavelength converter that performs wavelength conversion by passing a light beam emitted from the polarization direction conversion device through at least one nonlinear optical crystal.
6 4 . 請求項 6 3に記載の光源装置において、  6 4. The light source device according to claim 6,
前記複数の光ファイバから射出される光は赤外域及び可視域のいずれかの波 長を有し、 前記波長変換器から射出される光は紫外域の波長を有することを特 徴とする光源装置。  A light source device characterized in that light emitted from the plurality of optical fibers has a wavelength in one of an infrared region and a visible region, and light emitted from the wavelength converter has a wavelength in an ultraviolet region. .
6 5 . 請求項 6 4に記載の光源装置において、  65. In the light source device according to claim 64,
前記複数の光ファイバから射出される光は 1 5 4 7 n m付近の波長を有し、 前記波長変換器から射出される光は 1 9 3 . 4 n m付近の波長を有することを 特徴とする光源装置。  Light emitted from the plurality of optical fibers has a wavelength of about 147 nm, and light emitted from the wavelength converter has a wavelength of about 193.4 nm. apparatus.
6 6 . 希土類元素が添加されたフォスフェイ卜ガラス及び酸化ビスマス系ガ ラスのいずれかを主材とする光導波路部材を含み、 入射光を増幅する光増幅器 前記光増幅器から射出された光の波長を変換する波長変換器と;を備える光 源装置。 66. An optical amplifier that includes an optical waveguide member mainly composed of a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass, and amplifies incident light. A wavelength converter for conversion.
6 7 . 請求項 6 6に記載の光源装置において、 67. The light source device according to claim 66,
前記光導波路部材は、 光を導波するコアと、 前記コアの周囲に設けられたク ラッドとを有する光フアイバであることを特徴とする光源装置。  The light source device according to claim 1, wherein the optical waveguide member is an optical fiber having a core that guides light and a clad provided around the core.
6 8 . 請求項 6 7に記載の光源装置において、 68. In the light source device according to claim 67,
前記光ファイバは直線状に敷設されることを特徴とする光源装置。  The light source device, wherein the optical fiber is laid in a straight line.
6 9 . 請求項 6 7に記載の光源装置において、  69. The light source device according to claim 67,
前記光増幅器は、 少なくとも前記光ファイバを収容する容器を更に含むこと を特徴とする光源装置。  The light source device, wherein the optical amplifier further includes a container accommodating at least the optical fiber.
7 0 . 請求項 6 6に記載の光源装置において、  70. The light source device according to claim 66,
前記波長変換器は、波長変換を行う少なくとも 1つの非線形光学結晶を含む、 ことを特徴とする光源装置。  The light source device, wherein the wavelength converter includes at least one nonlinear optical crystal that performs wavelength conversion.
7 1 . レーザ光源から発振されるレーザ光の中心波長を所定の設定波長に維 持するための波長安定化制御方法であって、  7 1. A wavelength stabilization control method for maintaining a center wavelength of laser light oscillated from a laser light source at a predetermined set wavelength,
前記レーザ光の波長を検出する波長検出装置の検出基準波長の温度依存性を 予め測定する第 1工程と;  A first step of previously measuring the temperature dependence of a detection reference wavelength of a wavelength detection device for detecting the wavelength of the laser light;
前記設定波長に近い絶対波長を提供する絶対波長提供源から提供される絶対 波長に対して前記波長検出装置の検出基準波長をほぼ一致させる絶対波長キヤ リプレーシヨンを行う第 2工程と;  A second step of performing an absolute wavelength calibration for making a detection reference wavelength of the wavelength detection device substantially coincide with an absolute wavelength provided from an absolute wavelength providing source providing an absolute wavelength close to the set wavelength;
前記第 1工程で求めた前記温度依存性に基づいて、 前記波長検出装置の前記 検出基準波長を前記設定波長に設定する第 3工程とを含む波長安定化制御方法。  A third step of setting the detection reference wavelength of the wavelength detection device to the set wavelength based on the temperature dependency obtained in the first step.
7 2 . 請求項 7 1 に記載の波長安定化制御方法において、 7 2. The wavelength stabilization control method according to claim 7 1,
前記波長検出装置は、 フアブリペロー ·ェタロンであり、  The wavelength detector is a Fabry-Perot etalon,
前記第 1工程で前記波長検出装置の共鳴波長の温度依存性を測定し、 前記第 2工程で前記波長検出装置の温度を制御することにより前記共鳴波長 を前記絶対波長にほぼ一致させ、  Measuring the temperature dependence of the resonance wavelength of the wavelength detection device in the first step, and controlling the temperature of the wavelength detection device in the second step so that the resonance wavelength substantially matches the absolute wavelength;
前記第 3工程で前記波長検出装置の温度を制御することにより前記共鳴波長 を前記設定波長に設定することを特徴とする波長安定化制御方法。 By controlling the temperature of the wavelength detection device in the third step, the resonance wavelength is controlled. Is set to the set wavelength.
7 3 . 請求項 7 2に記載の波長安定化制御方法において、  7 3. The wavelength stabilization control method according to claim 7 2,
前記絶対波長提供源は、 前記レーザ光が入射する吸収セルであり、 前記第 2工程では、 前記吸収セルの前記設定波長に最も近い吸収線の吸収が 最大となり、 かつ前記波長検出装置の透過率が最大となるようにすることを特 徴とする波長安定化制御方法。  The absolute wavelength providing source is an absorption cell on which the laser light is incident.In the second step, the absorption of the absorption line closest to the set wavelength of the absorption cell is maximized, and the transmittance of the wavelength detection device is A wavelength stabilization control method characterized by maximizing the wavelength.
7 4 . 請求項 7 1に記載の波長安定化制御方法において、  74. In the wavelength stabilization control method according to claim 71,
前記第 1工程では前記レーザ光の中心波長の温度依存性をも予め計測し、 前記第 2工程では、 前記レーザ光の波長制御をも併せて行うことを特徴とす る波長安定化制御方法。  In the first step, the temperature dependency of the center wavelength of the laser light is also measured in advance, and in the second step, the wavelength control of the laser light is also performed.
7 5 . 請求項 7 1 に記載の波長安定化制御方法において、  75. In the wavelength stabilization control method according to claim 71,
前記第 3工程で前記検出基準波長が前記設定波長に設定された前記波長検出 装置の検出結果に基づいて前記レーザ光源からの前記レーザ光の波長を制御す る第 4工程を更に含むことを特徴とする波長安定化制御方法。  The method further includes a fourth step of controlling the wavelength of the laser light from the laser light source based on a detection result of the wavelength detection device in which the detection reference wavelength is set to the set wavelength in the third step. Wavelength stabilization control method.
7 6 . 請求項 7 4又は 7 5に記載の波長安定化制御方法において、 76. In the wavelength stabilization control method according to claim 74 or 75,
前記レーザ光の波長制御は、 前記レーザ光源の温度、 供給電流の少なくとも 一方を制御することにより行うことを特徴とする波長安定化制御方法。  A wavelength stabilization control method, wherein the wavelength control of the laser light is performed by controlling at least one of a temperature of the laser light source and a supply current.
7 7 . マスクに形成されたパターンを基板上に転写する露光装置であって、 赤外域から可視域までの範囲内の単一波長のレーザ光を発生する光発生部 と; 77. An exposure apparatus for transferring a pattern formed on a mask onto a substrate, wherein the light generating section generates a laser beam of a single wavelength within a range from an infrared region to a visible region;
前記光発生部の出力段に並列に配置された複数の光ファイバから成るフアイ バ群と;  A fiber group consisting of a plurality of optical fibers arranged in parallel at an output stage of the light generating unit;
前記各光ファイバからの光出力を個別にオン ·オフすることにより前記ファ ィバ群から出力されるレーザ光の光量を制御する光量制御装置と;  A light amount control device that controls the light amount of the laser light output from the fiber group by individually turning on and off the light output from each of the optical fibers;
前記各光ファイバから出力される前記レーザ光の波長を変換し、 前記レーザ 光の高調波である紫外光を出力する波長変換部と; 前記波長変換部から出力される前記紫外光を露光用照明光として前記マスク を照明する照明光学系と;備える露光装置。 A wavelength converter that converts a wavelength of the laser light output from each of the optical fibers, and outputs ultraviolet light that is a harmonic of the laser light; An exposure optical system that illuminates the mask using the ultraviolet light output from the wavelength conversion unit as exposure illumination light;
7 8 . 請求項 7 7に記載の露光装置において、 78. The exposure apparatus according to claim 77,
前記各光ファイバからの光出力のオン ·オフ状況に対応する出力強度マップ が予め記憶された記憶装置を更に備え、  Further comprising a storage device in which an output intensity map corresponding to the ON / OFF state of the optical output from each of the optical fibers is stored in advance,
前記光量制御装置は、 前記出力強度マップと所定の設定光量とに基づいて前 記各光ファイバからの光出力を個別にオン ·オフすることにより前記ファイバ 群から出力されるレーザ光の光量を制御することを特徴とする露光装置。 The light amount control device controls the light amount of the laser light output from the fiber group by individually turning on and off the light output from each of the optical fibers based on the output intensity map and a predetermined set light amount. An exposure apparatus, comprising:
7 9 . 請求項 7 7に記載の露光装置において、 79. The exposure apparatus according to claim 77,
前記光発生部は、 単一波長のレーザ光を発生する光源と、 該光源からの光を 所定周波数のパルス光に変換して出力する光変調器とを有し、  The light generation unit includes a light source that generates a single-wavelength laser light, and an optical modulator that converts light from the light source into pulsed light having a predetermined frequency and outputs the pulsed light.
前記光量制御装置は、 前記光変調器から出力される前記パルス光の周波数を 制御することにより、 前記フアイバ群から出力されるレーザ光の光量を更に制 御することを特徴とする露光装置。  An exposure apparatus, wherein the light amount control device further controls the light amount of laser light output from the fiber group by controlling the frequency of the pulse light output from the optical modulator.
8 0 · 請求項 7 9に記載の露光装置において、  80 ・ In the exposure apparatus according to claim 79,
前記光量制御装置は、 前記光変調器から出力される前記パルス光のピークパ ヮーを制御することにより、 前記フアイバ群から出力されるレーザ光の光量を 更に制御することを特徴とする露光装置。  An exposure apparatus, wherein the light quantity control device further controls the light quantity of laser light output from the fiber group by controlling a peak power of the pulse light output from the optical modulator.
8 1 . マスクに形成されたパターンを基板上に転写する露光装置であって、 単一波長の光を発生する光源と、 該光源からの光を所定周波数のパルス光に 変換して出力する光変調器とを有し、 赤外域から可視域までの範囲内の単一波 長のレーザ光を発生する光発生部と;  8 1. An exposure apparatus for transferring a pattern formed on a mask onto a substrate, comprising: a light source for generating light of a single wavelength; and light for converting light from the light source into pulsed light of a predetermined frequency and outputting the pulsed light. A light generator that has a modulator and generates a single-wavelength laser beam within a range from an infrared region to a visible region;
前記光発生部によって発生されたパルス光を増幅する少なくとも 1段のファ ィバ増幅器を含む光増幅部と;  An optical amplification unit including at least one fiber amplifier for amplifying the pulsed light generated by the light generation unit;
前記光変調器から出力される前記パルス光の周波数を制御することによリ前 記ファイバ増幅器からの出力光の光量を制御する光量制御装置と; 前記光増幅部から出力されるレーザ光の波長を変換し、 前記レ ザ光の高調 波である紫外光を出力する波長変換部と; A light amount control device for controlling a light amount of the output light from the fiber amplifier by controlling a frequency of the pulse light output from the optical modulator; A wavelength converter that converts the wavelength of the laser light output from the optical amplifier and outputs ultraviolet light that is a harmonic of the laser light;
前記波長変換部から出力される前記紫外光を露光用照明光として前記マスク を照明する照明光学系とを備える露光装置。  An exposure optical system that illuminates the mask with the ultraviolet light output from the wavelength conversion unit as illumination light for exposure.
8 2 . 請求項 8 1に記載の露光装置において、 8 2. The exposure apparatus according to claim 8,
前記光量制御装置は、 前記光変調器から出力される前記パルス光のピークパ ヮーを制御することにより前記光増幅部からの出力光の光量を更に制御するこ とを特徴とする露光装置。  An exposure apparatus, wherein the light quantity control device further controls the light quantity of the output light from the optical amplifying unit by controlling a peak power of the pulse light output from the optical modulator.
8 3 . マスクに形成されたパターンを基板上に転写する露光装置であって、 単一波長の光を発生する光源と、 該光源からの光を所定周波数のパルス光に 変換して出力する光変調器とを有し、 赤外域から可視域までの範囲内の単一波 長のレーザ光を発生する光発生部と;  83. An exposure apparatus for transferring a pattern formed on a mask onto a substrate, comprising: a light source for generating light of a single wavelength; and light for converting light from the light source into pulsed light of a predetermined frequency and outputting the pulsed light. A light generator that has a modulator and generates a single-wavelength laser beam within a range from an infrared region to a visible region;
前記光発生部によって発生されたパルス光を増幅する少なくとも 1段のファ ィバ増幅器を含む光増幅部と;  An optical amplification unit including at least one fiber amplifier for amplifying the pulsed light generated by the light generation unit;
前記光変調器から出力される前記パルス光のピークパワーを制御することに より前記光増幅部からの出力光の光量を制御する光量制御装置と;  A light amount control device that controls the light amount of the output light from the optical amplifying unit by controlling the peak power of the pulse light output from the optical modulator;
前記光増幅部から出力されるレーザ光の波長を変換し、 前記レーザ光の高調 波である紫外光を出力する波長変換部と;  A wavelength converter that converts a wavelength of the laser light output from the optical amplifier, and outputs an ultraviolet light that is a harmonic of the laser light;
前記波長変換部から出力される前記紫外光を露光用照明光として前記マスク を照明する照明光学系と;を備える露光装置。  An illumination optical system that illuminates the mask with the ultraviolet light output from the wavelength conversion unit as illumination light for exposure.
8 4 . マスクに形成されたパターンを基板上に繰り返し転写する露光装置で あって、  8 4. An exposure apparatus that repeatedly transfers a pattern formed on a mask onto a substrate,
単一波長の光を発生する光源と、 前記光源からの光をパルス光に変換する光 変調器とを有する光発生部と;  A light generation unit having a light source that generates light of a single wavelength, and a light modulator that converts light from the light source into pulsed light;
前記光発生部によって発生されたパルス光を増幅する少なくとも 1段のファ ィバ増幅器を含む光増幅部と; 前記増幅されたパルス光を前記マスクに照射して、 該マスクを介して前記基 板を露光する際に、 その露光対象領域の基板上の位置に応じて前記光変調器を 介して前記パルス光の周波数及びピークパワーの少なくとも一方を制御する制 御装置とを備える露光装置。 An optical amplification unit including at least one fiber amplifier for amplifying the pulsed light generated by the light generation unit; When the substrate is exposed through the mask by irradiating the mask with the amplified pulsed light, the pulsed light is transmitted through the optical modulator in accordance with the position of the exposure target area on the substrate. And a control device for controlling at least one of the frequency and the peak power.
8 5 . マスクに形成されたパターンを基板上に転写する露光装置であって、 単一波長の光を発生する光源と、 前記光源からの光をパルス光に変換する光 変調器とを有する光発生部と ;  85. An exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising: a light source that generates light of a single wavelength; and a light modulator that converts light from the light source into pulsed light. Generating part;
前記パルス光を増幅する光ファイバ増幅器を少なくとも各 1段含み、 前記光 発生部の出力段に並列に配置された複数の光経路から成る光増幅部と ; 前記光増幅部からの前記パルス光を前記マスクに照射して、 該マスクを介し て前記基板を露光する際に、 前記各光経路からの光出力を個別にオン ·オフす ることにより前記光増幅部から出力されるパルス光の光量を制御する制御装置 とを備える露光装置。  An optical amplifier comprising at least one optical fiber amplifier for amplifying the pulse light, and comprising a plurality of optical paths arranged in parallel at an output stage of the light generator; and When irradiating the mask and exposing the substrate through the mask, the light output from each optical path is individually turned on / off to thereby control the amount of pulsed light output from the optical amplifier. An exposure apparatus comprising: a control device that controls
8 6 . 請求項 8 4又は 8 5に記載の露光装置において、  86. The exposure apparatus according to claim 84 or 85,
前記光源は、 赤外域又は可視域のレーザ光を発生し、  The light source emits infrared or visible laser light,
前記光増幅部で増幅された前記パルス光を紫外光に波長変換する波長変換部 を更に備えることを特徴とする露光装置。  An exposure apparatus, further comprising: a wavelength converter for converting the wavelength of the pulse light amplified by the optical amplifier to ultraviolet light.
8 7 . レーザ光によりマスクを照明し、 該マスクのパターンを基板上に転写 する露光装置であって、  87. An exposure apparatus that illuminates a mask with a laser beam and transfers a pattern of the mask onto a substrate,
前記レーザ光を発振するレーザ光源と、 前記レーザ光の中心波長を所定の設 定波長に維持するための波長安定化に関連する前記レーザ光の光学特性をモニ 夕するビームモニタ機構と、 前記設定波長に近い絶対波長を提供する絶対波長 提供源とを有する光源装置と ;  A laser light source that oscillates the laser light, a beam monitor mechanism that monitors optical characteristics of the laser light related to wavelength stabilization for maintaining a center wavelength of the laser light at a predetermined set wavelength, and the setting. A light source device having an absolute wavelength providing source for providing an absolute wavelength close to the wavelength;
前記レーザ光源から発振される前記レーザ光の中心波長及び前記ビー厶モニ 夕機構の検出基準波長の温度依存性の測定データから成る温度依存性マップが 記憶された記憶装置と ; 前記絶対波長提供源から提供される絶対波長に対して前記ビームモニタ機構 の検出基準波長をほぼ一致させる絶対波長キャリブレーションを行うとともに、 前記温度依存性マップに基づいて前記検出基準波長を前記設定波長に一致させ る設定波長キャリブレーションを行う第 1の制御装置と; A storage device that stores a temperature dependence map including measurement data of the temperature dependence of the center wavelength of the laser light oscillated from the laser light source and the detection reference wavelength of the beam monitor mechanism; Absolute wavelength calibration is performed so that the detection reference wavelength of the beam monitor mechanism substantially matches the absolute wavelength provided from the absolute wavelength providing source, and the detection reference wavelength is set to the set wavelength based on the temperature dependence map. A first controller for performing a set wavelength calibration to match
前記光源装置から射出されるレーザ光の波長を前記設定波長キヤリプレーシ ヨンが終了した前記ビームモニタ機構のモニタ結果に基づいてフィードバック 制御しつつ、 前記レーザ光を前記マスクに照射して該マスクを介して前記基板 を露光する第 2の制御装置と;を備える露光装置。  The laser beam is emitted to the mask through the mask while feedback-controlling the wavelength of the laser beam emitted from the light source device based on the monitoring result of the beam monitoring mechanism after the set wavelength calibration is completed. A second control device for exposing the substrate.
8 8 . 請求項 8 7に記載の露光装置において、 88. The exposure apparatus according to claim 87,
前記マスクから出射された前記レーザ光を前記基板に投射する投影光学系 と;  A projection optical system for projecting the laser light emitted from the mask onto the substrate;
前記投影光学系の近傍の環境に関連する物理量を測定する環境センサと; 前記第 2の制御装置により前記基板の露光が開始されてから所定のタイミン グ毎に、 前記環境センサの計測値に基づいて標準状態からの前記物理量の変化 に起因する前記投影光学系の結像特性の変動分をほぼ相殺するための波長変更 量を計算で求め、 該波長変更量に応じて前記設定波長を変更する第 3の制御装 置と;を更に備えることを特徴とする露光装置。  An environment sensor for measuring a physical quantity related to an environment in the vicinity of the projection optical system; and at predetermined timings after exposure of the substrate is started by the second control device, based on a measurement value of the environment sensor. Calculating a wavelength change amount for substantially canceling a change in the imaging characteristic of the projection optical system due to the change in the physical amount from the standard state, and changing the set wavelength according to the wavelength change amount. An exposure apparatus, further comprising: a third control device.
8 9 . 請求項 8 8に記載の露光装置において、  8 9. The exposure apparatus according to claim 8,
前記投影光学系の結像特性を補正する結像特性補正装置を更に備え、 前記結像特性補正装置は、 前記第 3の制御装置による前記設定波長の変更の 度毎に、 前記設定波長の変更により補正される前記投影光学系の結像特性の変 動分を除く、 結像特性変動を補正することを特徴とする露光装置。  The image forming apparatus further includes an image forming characteristic correcting device that corrects an image forming characteristic of the projection optical system, wherein the image forming characteristic correcting device changes the set wavelength every time the third control device changes the set wavelength. An exposure apparatus that corrects the imaging characteristic variation except for a variation in the imaging characteristic of the projection optical system corrected by the following.
9 0 . 請求項 8 7に記載の露光装置において、  90. The exposure apparatus according to claim 87,
前記光源装置は、 前記レーザ光源からのレーザ光を増幅するフアイバ増幅器 と;  A fiber amplifier for amplifying laser light from the laser light source;
前記増幅されたレーザ光の波長を紫外域の波長に変換する非線形光学結晶を 含む波長変換器と;を更に備えることを特徴とする露光装置。 A nonlinear optical crystal that converts the wavelength of the amplified laser light into a wavelength in the ultraviolet region. An exposure apparatus, further comprising: a wavelength converter.
9 1 . エネルギビームにより感光剤が塗布された基板を露光する露光装置で あって、  9 1. An exposure apparatus for exposing a substrate coated with a photosensitive agent by an energy beam,
前記エネルギビームを発生するビ一厶源と;  A beam source for generating the energy beam;
前記ビーム源から出力される前記エネルギビームの波長を変更する波長変更 装置と;  A wavelength changing device for changing a wavelength of the energy beam output from the beam source;
前記波長変更装置により前記波長が変更されたとき、 その波長変更に伴って 生じる前記感光剤の感度特性の変化量に応じて前記基板に与えられる積算露光 量を制御する露光量制御装置と;を備える露光装置。  When the wavelength is changed by the wavelength changing device, an exposure amount control device that controls an integrated exposure amount given to the substrate in accordance with an amount of change in sensitivity characteristics of the photosensitive agent caused by the wavelength change. Exposure equipment provided.
9 2 . 露光用ビームを基板に照射することにより、 所定のパターンを基板に 転写する露光装置であって、  9 2. An exposure apparatus for transferring a predetermined pattern onto a substrate by irradiating the substrate with an exposure beam,
赤外域及び可視域のいずれかの波長の光を射出する複数の光ファイバと; 前記複数の光ファイバを介した同一波長の複数の光束の偏光状態を揃える偏 光調整装置と;  A plurality of optical fibers for emitting light of any one of infrared and visible wavelengths; a polarization adjusting device for aligning the polarization states of a plurality of light beams of the same wavelength via the plurality of optical fibers;
前記複数の光ファイバを介した全ての光束を同一の偏光方向を有する複数の 直線偏光光束に変換する偏光方向変換装置と;  A polarization direction conversion device that converts all light beams transmitted through the plurality of optical fibers into a plurality of linearly polarized light beams having the same polarization direction;
前記偏光方向変換装置から射出された光束を、 少なくとも 1つの非線形光学 結晶を介させることにより、 波長変換を行い、 紫外域の波長の光を射出する波 長変換器と;  A wavelength converter that performs wavelength conversion by passing a light beam emitted from the polarization direction conversion device through at least one nonlinear optical crystal, and emits light having a wavelength in an ultraviolet region;
前記波長変換器から射出される光を前記露光用ビームとして前記基板に照射 する光学系と;を備える露光装置。  An optical system for irradiating the substrate with light emitted from the wavelength converter as the exposure beam.
9 3 . 露光光を基板に照射して所定のパターンを形成する露光装置であって、 希土類元素が添加されたフォスフェイ卜ガラス及び酸化ビスマス系ガラスの いずれかを主材とする光導波路部材を含み、 入射光を増幅する光増幅器と; 前記光増幅器から射出された光の波長を変換する波長変換器と;  9 3. An exposure apparatus for irradiating exposure light to a substrate to form a predetermined pattern, including an optical waveguide member mainly composed of either a phosphate glass to which a rare earth element is added or a bismuth oxide-based glass. An optical amplifier for amplifying incident light; a wavelength converter for converting the wavelength of light emitted from the optical amplifier;
前記波長変換器から射出される光を前記露光光として前記基板に照射する光 学系とを備える露光装置。 Light for irradiating the substrate with light emitted from the wavelength converter as the exposure light An exposure apparatus having a science system.
9 4 . 請求項 9 3に記載の露光装置において、  94. The exposure apparatus according to claim 93,
前記光導波路部材は、 光を導波するコアと、 前記コアの周囲に設けられたク ラッドとを有する光ファイバであることを特徴とする露光装置。  The exposure apparatus according to claim 1, wherein the optical waveguide member is an optical fiber having a core that guides light and a clad provided around the core.
9 5 . 請求項 9 3に記載の露光装置において、 95. The exposure apparatus according to claim 93,
前記波長変換器は、 2 0 0 n m以下の波長の前記露光光を発生することを特 徴とする露光装置。  An exposure apparatus, wherein the wavelength converter generates the exposure light having a wavelength of 200 nm or less.
9 6 . マスクに形成されたパターンを基板上に繰り返し転写する露光方法で あって、  9 6. An exposure method for repeatedly transferring a pattern formed on a mask onto a substrate,
パルス光をファイバ増幅器を用いて少なくとも 1回増幅する第 1工程と; 前記増幅されたパルス光を前記マスクに照射し、 該マスクを介して前記基板 上の露光対象領域を露光する第 2工程と;  A first step of amplifying the pulsed light at least once using a fiber amplifier; and a second step of irradiating the mask with the amplified pulsed light and exposing a region to be exposed on the substrate via the mask. ;
前記第 1工程の処理に先立って、 光源からのレーザ光を前記パルス光に変換 するとともに、 前記露光対象領域の基板上の位置に応じて前記パルス光の周波 数及びピークパワーの少なくとも一方を制御する第 3工程と;を含む露光方法。  Prior to the processing in the first step, the laser light from the light source is converted into the pulse light, and at least one of the frequency and the peak power of the pulse light is controlled according to the position of the exposure target area on the substrate. A third step of performing exposure.
9 7 . 請求項 9 6に記載の露光方法において、 97. In the exposure method according to claim 96,
前記ファイバ増幅器は、 複数並列に設けられ、  A plurality of the fiber amplifiers are provided in parallel,
前記第 1工程では、 選択されたファイバ増幅器のみを用いて前記パルス光の 増幅を行うことを特徴とする露光方法。  The exposure method, wherein in the first step, the pulse light is amplified using only the selected fiber amplifier.
9 8 . 請求項 9 6に記載の露光方法において、 98. In the exposure method according to claim 96,
前記光源は、 赤外域又は可視域のレーザ光を発生し、  The light source emits infrared or visible laser light,
前記パルス光が前記マスクに照射される前に前記増幅されたパルス光を紫外 光に波長変換する第 4工程を更に含むことを特徴とする露光方法。  An exposure method, further comprising a fourth step of converting the wavelength of the amplified pulse light into ultraviolet light before the pulse light is irradiated on the mask.
9 9 . レーザ光により基板を露光して所定のパターンを基板上に形成する露 光方法であって、 9 9. An exposure method for exposing a substrate with a laser beam to form a predetermined pattern on the substrate,
露光開始に先立って、 前記レーザ光の波長を検出する波長検出装置の検出基 準波長の温度依存性を予め測定する第 1副工程と、 前記設定波長に近い絶対波 長を提供する絶対波長提供源から提供される絶対波長に対して前記波長検出装 置の検出基準波長をほぼ一致させる絶対波長キヤリブレーションを行う第 2副 工程と、 前記第 1副工程で求めた前記温度依存性に基づいて、 前記波長検出装 置の前記検出基準波長を前記設定波長に設定する第 3副工程との処理を順次行 う第 1工程と; Prior to the start of exposure, the detection base of the wavelength detection device for detecting the wavelength of the laser light A first sub-step of measuring the temperature dependence of the quasi-wavelength in advance; and A second sub-step of performing an absolute wavelength calibration to make the wavelengths substantially coincide with each other; and a second sub-step of setting the detection reference wavelength of the wavelength detection device to the set wavelength based on the temperature dependency obtained in the first sub-step. A first step in which the processing of the three sub-steps is performed sequentially;
しかる後、 前記第 3副工程で前記検出基準波長が前記設定波長に設定された 前記波長検出装置の検出結果に基づいて前記レーザ光源からの前記レーザ光の 波長を制御しつつ、 基板を前記レーザ光で繰り返し露光する第 2工程と;を含 む露光方法。  Thereafter, while controlling the wavelength of the laser light from the laser light source based on the detection result of the wavelength detection device in which the detection reference wavelength is set to the set wavelength in the third sub-step, the substrate is irradiated with the laser. A second step of repeatedly exposing with light.
1 0 0 . 請求項 9 9に記載の露光方法において、  100. The exposure method according to claim 99,
前記レーザ光の経路に配置された光学系が更に設けられ、  An optical system arranged in the path of the laser light is further provided,
前記光学系の光学性能の変動をキャンセルするために前記設定波長を変更す る第 3工程を更に含むことを特徴とする露光方法。  An exposure method, further comprising a third step of changing the set wavelength in order to cancel a change in optical performance of the optical system.
1 0 1 . 露光光を、 光学系を介して基板に照射して所定のパターンを形成す る露光装置の製造方法において、  101. A method for manufacturing an exposure apparatus, comprising irradiating exposure light to a substrate via an optical system to form a predetermined pattern.
前記光学系の特性の調整を、 請求項 6 6 - 7 0のいずれか一項に記載の光源 装置が発生した前記露光光の波長を含む所定幅の波長帯に属する波長の光を使 用して行うことを特徴とする露光装置の製造方法。  The characteristic of the optical system is adjusted by using light of a wavelength belonging to a wavelength band having a predetermined width including the wavelength of the exposure light generated by the light source device according to any one of claims 66 to 70. A method of manufacturing an exposure apparatus.
1 0 2 . リソグラフイエ程を含むデバイス製造方法であって、 102. A device manufacturing method including a lithographic process,
前記リソグラフイエ程で、 請求項 7 7 ~ 8 5、 8 7 ~ 9 5のいずれか一項に 記載の露光装置を用いて露光を行うことを特徴とするデバイス製造方法。  A device manufacturing method, comprising performing exposure using the exposure apparatus according to any one of claims 77 to 85 and 87 to 95 in the lithographic process.
1 0 3 . 請求項 1 0 2に記載のデバイス製造方法により製造されたデバイス。  103. A device manufactured by the device manufacturing method according to claim 102.
1 0 4 . リソグラフイエ程を含むデバイス製造方法であって、 104. A device manufacturing method including a lithographic process,
前記リソグラフイエ程で、 請求項 9 6〜 1 0 0のいずれか一項に記載の露光 方法を用いることを特徴とするデバイス製造方法。 A device manufacturing method using the exposure method according to any one of claims 96 to 100 in the lithographic process.
05. 請求項 1 04に記載のデバイス製造方法により製造されたデバイス t 05. Device t manufactured by the device manufacturing method according to claim 104
PCT/JP2000/005875 1999-09-10 2000-08-30 Light source and wavelength stabilization control method, exposure apparatus and exposure method, method for producing exposure apparatus, and device manufacturing method and device WO2001020733A1 (en)

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